Control device for human-powered vehicles

Abstract

The present invention provides a control device that can properly control a motor without using a torque sensor. [Solution] A control device for a human-powered vehicle, comprising a control unit configured to control a motor that provides assist force to the human-powered vehicle, wherein the control unit determines the assist force according to the driving information and driving resistance information of the human-powered vehicle, without using the detection value of a torque sensor that detects the human-powered torque input to the human-powered vehicle.

Description

Technical Field

[0001] The present disclosure relates to the technology of a control device for a human-powered vehicle.

Background Art

[0002] Conventionally, control devices for human-powered vehicles are known. For example, Patent Document 1 discloses a technology of a control device that controls a motor that applies an assisting force to a human-powered vehicle in accordance with a detection value of a torque sensor.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of Invention

Problem to be Solved by the Invention

[0004] There is a demand for a technology that can appropriately control a motor without using a torque sensor.

[0005] One of the objects of the present disclosure is to provide a control device that can appropriately control a motor without using a torque sensor.

Means for Solving the Problem

[0006] A control device according to a first aspect of the present disclosure is a control device for a human-powered vehicle, comprising a control unit configured to control a motor that applies an assisting force to the human-powered vehicle, wherein the control unit determines the assisting force in accordance with traveling information and traveling resistance information of the human-powered vehicle, without using a detection value of a torque sensor that detects a human-powered torque input to the human-powered vehicle. According to the control device of the first aspect, the motor can be appropriately controlled without using a torque sensor.

[0007] In the control device according to the second aspect that follows the first aspect, the control unit applies the determined assisting force to the human-powered vehicle. According to the control device on the second side, appropriate assist force can be applied to a human-powered vehicle even without using a torque sensor.

[0008] In a control device according to the first or second aspect, the control unit is configured to control a motor in a human-powered vehicle that does not have a torque sensor. The control device on the third side can help reduce the cost of human-powered vehicles.

[0009] In a control device of the fourth side that conforms to any one of the first to third sides, the driving information includes at least one of the vehicle speed, wheel speed, and cadence of a human-powered vehicle. According to the control device on the fourth side, the assist force can be determined according to at least one of the vehicle speed, wheel speed, and cadence.

[0010] In a control device of a fifth side that conforms to any one of the first to fourth sides, the running resistance information includes at least one of the acceleration resistance, gradient resistance, and rolling resistance of a human-powered vehicle. According to the control device on the fifth side, the assist force can be determined in accordance with at least one of the acceleration resistance, gradient resistance, and rolling resistance.

[0011] In the control device of the sixth side corresponding to the fifth side, the control unit performs acceleration resistance determination processing to determine the acceleration resistance based on the weight of the human-powered vehicle and the acceleration in the direction of travel. According to the control device on the sixth side, the acceleration resistance can be determined by the weight of the human-powered vehicle and the acceleration in the direction of travel.

[0012] In the control device of the seventh side according to the sixth side, the control unit performs acceleration resistance determination processing in at least one of the following cases: when the cadence of the crank arm of the human-powered vehicle is greater than a predetermined threshold, and when a predetermined time has elapsed since the rotation of the crank arm of the human-powered vehicle was detected. According to the control device on the seventh side, the assist force can be determined in accordance with the acceleration resistance in at least one of the following cases: when the cadence is high, and when a predetermined time has elapsed since the rotation of the crank arm was detected.

[0013] In the control device of the eighth side according to the sixth or seventh side, the control unit performs a gradient resistance determination process that determines the gradient resistance based on the weight of the human-powered vehicle and the incline of the road surface on which the human-powered vehicle travels. According to the control device on the eighth side, the gradient resistance can be determined by the weight of the human-powered vehicle and the incline of the road surface on which the human-powered vehicle is traveling.

[0014] In the control device of the ninth side corresponding to the eighth side, the control unit performs gradient resistance determination processing in at least one of the following cases: when the cadence of the crank arm of the human-powered vehicle is greater than a predetermined threshold, and when a predetermined time has elapsed since the rotation of the crank arm of the human-powered vehicle was detected. According to the control device on the ninth side, the assist force can be determined according to the gradient resistance in at least one of the following cases: when the cadence is high, and when a predetermined time has elapsed since the rotation of the crank arm was detected.

[0015] In a control device of the tenth side that conforms to any one of the fifth to ninth sides, the control unit performs a rolling resistance determination process that determines the rolling resistance based on the weight of the human-powered vehicle and the coefficient of friction of the road surface on which the human-powered vehicle travels. According to the control device on the 10th side, the rolling resistance can be determined by the weight of the human-powered vehicle and the coefficient of friction of the road surface on which the human-powered vehicle is traveling.

[0016] In the control device of the 11th side corresponding to the 10th side, the control unit performs rolling resistance determination processing in at least one of the following cases: when the cadence of the crank arm of the human-powered vehicle is greater than a predetermined threshold, and when a predetermined time has elapsed since the rotation of the crank arm of the human-powered vehicle was detected. According to the control device on the 11th side, the assist force can be determined according to the rolling resistance in at least one of the following cases: when the cadence is high, and when a predetermined time has elapsed since the rotation of the crank arm was detected.

[0017] In a control device of the 12th side that follows any one of the 1st to 11th sides, the control unit determines the assist force for starting to pedal based on a predetermined acceleration for starting to pedal, the slope of the road surface on which the human-powered vehicle stops, and vehicle information of the human-powered vehicle. According to the control device on the 12th side, the assist force for starting to pedal can be determined based on the acceleration at the start of pedaling, the slope of the road surface where the human-powered vehicle is stopped, and the vehicle information of the human-powered vehicle.

[0018] In the control device of the 13th side corresponding to the 1st to 12th sides, the control unit determines the assist force as the assist force for starting to pedal, based on a predetermined reference assist force, when the amount of rotation of the crank arm of the human-powered vehicle is less than or equal to a predetermined amount of rotation. According to the control device on the 13th side, when the amount of rotation of the crank is less than or equal to the amount of rotation, the assist force can be determined based on a predetermined reference assist force.

[0019] In the control device on the 14th side according to the 12th side, the vehicle information includes at least one of the total weight of the human-powered vehicle, the circumference of the tires, and the gear ratio. According to the control device on the 14th side, the assist force for starting to pedal can be determined according to at least one of the total weight of the human-powered vehicle, the tire circumference, and the gear ratio.

[0020] In the control device of the 15th side according to the 14th side, the control unit determines the gear ratio based on the vehicle speed and cadence of the human-powered vehicle. According to the control device on side 15, the gear ratio can be determined in a human-powered vehicle that does not have a sensor for detecting the gear ratio.

[0021] In a control device of the 16th side that follows any one of the 1st to 15th sides, the control unit reduces the assist force when the cadence drops sharply. According to the control device on the 16th side, the assist force can be appropriately controlled.

[0022] In a control device according to the 17th side which follows any one of the 1st to 16th sides, the human-powered vehicle is provided with a one-way clutch in the power transmission path from the crankshaft to the front sprocket, which has a clutch engagement state that transmits power from the crankshaft to the front sprocket when the crankshaft rotates in a first rotational direction, and a clutch disengagement state that does not transmit power from the crankshaft to the front sprocket when the crankshaft rotates in a second rotational direction opposite to the first rotational direction, and the control unit reduces the assist force when the one-way clutch is in the clutch disengagement state. According to the control device on the 17th side, the assist force can be appropriately controlled.

[0023] In the control device of the 18th side corresponding to the 17th side, the control unit detects the clutch engagement state or clutch disengagement state of the one-way clutch based on the rotational speed of the motor and the cadence of the crank arm of the human-powered vehicle. According to the control device on side 18, the clutch engagement state and the clutch disengagement state can be detected based on the motor's rotational speed and the cadence of the human-powered vehicle. [Effects of the Invention]

[0024] According to the control device of this disclosure, the motor can be properly controlled without using a torque sensor. [Brief explanation of the drawing]

[0025] [Figure 1] A side view showing a human-powered vehicle equipped with a control device according to the first embodiment. [Figure 2] A cross-sectional view showing the drive unit. [Figure 3] A block diagram showing an example of the electrical configuration of a human-powered vehicle equipped with a control device. [Figure 4] A state transition diagram showing the state in which assistance is permitted and the state in which assistance is not permitted. [Figure 5] This diagram shows the relationship between the amount of rotation of the crank arm and the gear ratio when the front wheel travels 0.1m. [Figure 6] (a) is a diagram showing an example of human torque, cadence, and vehicle speed during pedaling. (b) is a diagram showing an example of a pulse signal during pedaling. (c) is a diagram showing an example of assist enabled state and assist disabled state during pedaling. [Figure 7] (a) is a diagram showing the human torque, cadence, and vehicle speed of a human-powered vehicle when it comes to a complete stop. (b) is a diagram showing the pulse signal of a human-powered vehicle when it comes to a complete stop. (c) is a diagram showing an example of the assist enabled state and the assist disabled state of a human-powered vehicle when it comes to a complete stop. [Figure 8] A diagram illustrating the procedure for determining assist torque in a typical drive unit. [Figure 9] A diagram illustrating the procedure for determining the assist torque in the first embodiment. [Figure 10] A flowchart showing an example of a motor control flow. [Figure 11] This diagram shows an example of the data flow when controlling a motor by determining the assist torque. [Figure 12] A flowchart showing the subflow of acceleration resistance. [Figure 13] An explanatory diagram showing gradient resistance. [Figure 14] A flowchart showing the gradient resistance subflow. [Figure 15] A flowchart showing the total torque subflow. [Figure 16] (a) is a diagram showing an example of total torque. (b) is a diagram showing an example of cadence. [Figure 17] A flowchart showing an example of the engagement state determination flow. [Figure 18] (a) is a diagram showing an example of human torque, converted speed, and cadence. (b) is a diagram showing an example of the engagement state of the first one-way clutch. [Figure 19] A flowchart showing the torque update flow. [Figure 20] A state transition diagram related to pedal status. [Figure 21] A flowchart showing an example of the gear ratio estimation flow. [Figure 22] A diagram showing an example of weighting coefficients in a zero-start state. [Figure 23] A figure showing an example of weighting coefficients in the restart state. [Modes for carrying out the invention]

[0026] (First Embodiment) A control device 31 according to the first embodiment will be described. Figures 1 to 23 will be used to describe the control device 31 according to the first embodiment.

[0027] Human-powered vehicle 1 is a vehicle having at least one wheel 15 and capable of being driven by at least human power. Human-powered vehicle 1 includes various types of bicycles, such as mountain bikes, road bikes, city bikes, cargo bikes, handbikes, and recumbent bikes. The number of wheels 15 that human-powered vehicle 1 has is not limited. Human-powered vehicle 1 includes, for example, unicycles and vehicles having two or more wheels 15. Human-powered vehicle 1 is not limited to vehicles that can be driven solely by human power. Human-powered vehicle 1 includes e-bikes that utilize the driving force of an electric motor for propulsion in addition to human power. E-bikes include electric assist bicycles in which propulsion is assisted by an electric motor. Hereinafter, in embodiments, human-powered vehicle 1 will be described as a bicycle.

[0028] In this specification, the following directional terms, “front,” “rear,” “forward,” “backward,” “left,” “right,” “side,” “upward,” and “downward,” as well as any other similar directional terms, refer to those directions determined with respect to the rider facing the handlebars 13 at a reference position of the human-powered vehicle 1 (e.g., on the saddle or seat 12).

[0029] As shown in Figures 1 and 3, the human-powered vehicle 1 comprises a crank 10, a frame 11, a seat 12, handlebars 13, a front fork 14, wheels 15, a drive mechanism 16, a transmission 17, a battery 18, a drive unit 19, and a control system 30. The crank 10 shown in Figure 1 includes a crank shaft 10a that is rotatable relative to the frame 11, and a pair of crank arms 10b provided at both axial ends of the crank shaft 10a. Pedals 10c are connected to each of the pair of crank arms 10b.

[0030] A seat 12 is provided on the frame 11 via a seat post 12a. The frame 11 rotatably supports the handlebars 13 and the front fork 14. The handlebars 13 are configured to be gripped by the rider. As the handlebars 13 rotate relative to the frame 11, the front fork 14 rotates, changing the direction of travel of the human-powered vehicle 1.

[0031] The wheel 15 includes a front wheel 15a and a rear wheel 15b. The front wheel 15a is rotatably mounted on the front fork 14. The rear wheel 15b is rotatably mounted on the frame 11. The drive mechanism 16 connects the crank 10 and the rear wheel 15b to each other. The drive mechanism 16 includes a first rotating body 16a, a second rotating body 16b, and a power transmission unit 16c.

[0032] The first rotating body 16a includes, for example, one front sprocket 16d. The first rotating body 16a may include multiple front sprockets 16d. One front sprocket 16d is configured to rotate integrally with the crankshaft 10a when the crankshaft 10a rotates in a first rotational direction. The first rotational direction is the direction in which the human-powered vehicle 1 moves forward.

[0033] As the crankshaft 10a rotates in the first rotational direction, one front sprocket 16d rotates, and the human-powered driving force is transmitted to the rear wheel 15b. This transmission of human-powered driving force to the rear wheel 15b causes the human-powered vehicle 1 to move forward.

[0034] The second rotating body 16b is configured to output human-powered driving force to the rear wheel 15b. The second rotating body 16b includes, for example, a plurality of rear sprockets 16e. The second rotating body 16b may include one rear sprocket 16e. The plurality of rear sprockets 16e are connected to the rear wheel 15b. The power transmission unit 16c transmits the rotational force of the first rotating body 16a to the second rotating body 16b. The power transmission unit 16c includes a chain 16f. The configuration of the drive mechanism 16 is not limited to this embodiment. The drive mechanism 16 may connect the crank 10 and the rear wheel 15b to each other by, for example, pulleys and a belt.

[0035] A one-way clutch may be provided in the power transmission path from the rear sprocket 16e to the rear wheel 15b, configured to transmit the rotation of the rear sprocket 16e along the first rotational direction to the rear wheel 15b, and not to transmit the rotation of the rear wheel 15b along the first rotational direction to the rear sprocket 16e.

[0036] The gear shifter 17 changes the gear ratio of the human-powered vehicle 1. The gear ratio is the ratio of the rotational speed of the rear wheel 15b to the rotational speed of the crankshaft 10a. The gear ratio is expressed, for example, as the ratio of the total number of teeth on the rear sprocket 16e with which the chain 16f engages to the total number of teeth on the front sprocket 16d with which the chain 16f engages. The gear shifter 17 includes at least one of an external gear shifter and an internal gear shifter. In this embodiment, the gear shifter 17 includes an external gear shifter. If the gear shifter 17 includes an external gear shifter, the external gear shifter includes at least one of a front derailleur and a rear derailleur 17a. In this embodiment, the external gear shifter includes a rear derailleur 17a. The rear derailleur 17a is configured to allow the chain 16f to be re-engaged between a plurality of rear sprockets 16e when a gear shifting device provided on the handlebars 13 is operated by the rider.

[0037] The battery 18 supplies power to components mounted on the human-powered vehicle 1. These components include, for example, a drive unit 19. The battery 18 includes, for example, at least one non-rechargeable battery and a rechargeable battery. The rechargeable battery is configured to be rechargeable by power from an external power source. The battery 18 is provided on the frame 11. In this embodiment, at least a portion of the battery 18 is located in the internal space of the frame 11.

[0038] The drive unit 19 is configured to provide an assist force to the human-powered vehicle 1 in response to the human-powered force input to the human-powered vehicle 1. The human-powered force is indicated by, for example, torque and at least one of power. When the human-powered force is indicated by torque, it may be referred to as human-powered torque. When the human-powered force is indicated by power, it may be referred to as human-powered power. The assist force is indicated by, for example, torque and at least one of power. When the assist force is indicated by torque, it may be referred to as assist torque. When the assist force is indicated by power, it may be referred to as assist power.

[0039] As shown in Figure 2, the drive unit 19 includes a housing 20, an output shaft 21, a transmission shaft 22, a first one-way clutch 23, a motor 24, a reduction gear 25, and a second one-way clutch 26.

[0040] The housing 20 is formed in a hollow shape. The housing 20 includes a pair of through holes 20a that penetrate the housing 20 in the axial direction with respect to the rotational axis C10 of the crankshaft 10a. The crankshaft 10a is inserted through the pair of through holes 20a. The crankshaft 10a protrudes into the external space of the housing 20 through the pair of through holes 20a.

[0041] The output shaft 21 is connected directly or indirectly to the crankshaft 10a. The output shaft 21 has a substantially cylindrical shape. The output shaft 21 is positioned coaxially with the crankshaft 10a. The output shaft 21 is positioned radially to the crankshaft 10a with respect to the rotational axis C10 of the crankshaft 10a. A portion of the output shaft 21 protrudes into the external space of the housing 20 through one of a pair of through holes 20a. The front sprocket 16d is fixed to the output shaft 21 in the external space of the housing 20. In Figure 2, the front sprocket 16d is not shown.

[0042] The crankshaft 10a is rotatably supported relative to the housing 20 by a first bearing 20b. The output shaft 21 is rotatably supported relative to the housing 20 by a second bearing 20c. The first bearing 20b and the second bearing 20c are located, for example, in the internal space of the housing 20. The output shaft 21 rotatably supports the crankshaft 10a via a third bearing 20d. The third bearing 20d is located between the outer circumferential surface of the crankshaft 10a and the inner circumferential surface of the output shaft 21.

[0043] The transmission shaft 22 and the first one-way clutch 23 are positioned between the crankshaft 10a and the output shaft 21 in the transmission path of human-powered driving force from the crankshaft 10a to the rear sprocket 16e. The transmission shaft 22 is positioned coaxially with the crankshaft 10a. The transmission shaft 22 is fixed to the outer circumferential surface of the crankshaft 10a. A portion of the transmission shaft 22 is positioned in the internal space of the output shaft 21. The first one-way clutch 23 is positioned between the outer circumferential surface of the transmission shaft 22 and the inner circumferential surface of the output shaft 21. The first one-way clutch 23 is configured to rotate the front sprocket 16d when the crankshaft 10a rotates in a first rotational direction, and to allow relative rotation between the crankshaft 10a and the front sprocket 16d when the crankshaft 10a rotates in a second rotational direction. The front sprocket 16d can rotate independently of the crankshaft 10 by being connected to the crankshaft 10a via the first one-way clutch 23.

[0044] The motor 24 is configured to transmit rotational force to the chain 16f, for example, via an output shaft 21. The motor 24 is housed in the housing 20. The motor 24 is located in the internal space of the housing 20. The motor 24 includes a motor output shaft 24a.

[0045] The gearbox 25 is configured to connect the motor 24 and the output shaft 21. The gearbox 25 is housed in the housing 20. The gearbox 25 is positioned in the internal space of the housing 20. The gearbox 25 includes, for example, a plurality of external gears 25a. When the motor output shaft 24a rotates, the plurality of external gears 25a rotate. The rotation of the plurality of external gears 25a transmits the motor driving force to the output shaft 21, causing the output shaft 21 to rotate. The rotation of the plurality of external gears 25a reduces the rotational speed of the output shaft 21 relative to the rotational speed of the motor output shaft 24a.

[0046] The second one-way clutch 26 is provided on the reduction gear 25. The second one-way clutch 26 is configured to transmit the rotation of the motor output shaft 24a to the output shaft 21, and not to transmit the rotation of the output shaft 21 to the motor output shaft 24a.

[0047] The control system 30 shown in Figure 3 comprises a control device 31 and a detection unit 32. The control device 31 is a control device 31 for a human-powered vehicle and includes a control unit 31b configured to control a motor 24 that provides assist force to the human-powered vehicle 1. In this embodiment, the control device 31 further comprises a storage unit 31a.

[0048] The storage unit 31a is configured to store a control program and information used in control processing. The storage unit 31a includes, for example, at least one of a non-volatile memory, a volatile memory, and a hard disk.

[0049] The control unit 31b is configured to perform control over the control system 30. The control unit 31b includes an arithmetic processing unit that executes a predetermined control program. The arithmetic processing unit includes, for example, a CPU (Central Processing Unit) or an MPU (Micro Processing Unit). The control unit 31b may include one or more microcomputers. The control unit 31b further includes an inverter circuit connected to the motor 24.

[0050] The detection unit 32 is configured to detect various information of the human-powered vehicle 1. The detection unit 32 is configured to communicate with the control unit 31b via an electrical cable or a wireless communication device. The detection unit 32 can output a signal to the control unit 31b according to the detection result. The detection unit 32 includes a vehicle speed sensor 33, a cadence sensor 34, a tilt sensor 35, an acceleration sensor 36, and a rotation sensor 37.

[0051] The vehicle speed sensor 33 is configured to detect the vehicle speed of the human-powered vehicle 1. The vehicle speed sensor 33 detects the vehicle speed based, for example, on the rotational speed of the wheels 15. In this embodiment, the vehicle speed sensor 33 detects the vehicle speed based on the rotational speed of the front wheels 15a, which are non-driven wheels. In this specification, the front wheels 15a may be described as non-driven wheels. The vehicle speed sensor 33 includes a wheel speed sensor 33a capable of detecting the rotational speed of the front wheels 15a. The wheel speed sensor 33a includes a rotating body mounted on the front wheels 15a so as to rotate integrally with the front wheels 15a.

[0052] The rotating body is formed, for example, in the shape of a disc. Multiple slits are formed on the rotating body at equal intervals along the circumferential direction. The total number of slits in this embodiment is 90. The wheel speed sensor 33a is configured to output a pulse signal when it detects a slit on the rotating body based on a change in magnetic flux corresponding to the rotation of the rotating body. The vehicle speed sensor 33 detects the vehicle speed of the human-powered vehicle 1 based on, for example, the pulse signal from the wheel speed sensor 33a and the tire circumference of the front wheel 15a.

[0053] The total number of slits in the rotating body is not limited to this embodiment. The total number of slits may be, for example, 56. It is preferable that the total number of slits be 2 or more. By having a total number of slits of 2 or more, the wheel speed sensor 33a outputs multiple pulse signals during one rotation of the front wheel 15a. The vehicle speed sensor 33 can precisely detect the vehicle speed of the human-powered vehicle 1 based on multiple pulse signals, thereby improving its resolution.

[0054] The vehicle speed sensor 33 may detect the vehicle speed in accordance with information other than the rotational speed of the front wheels 15a. For example, the vehicle speed sensor 33 may detect the vehicle speed in accordance with at least one of the rotational speed of the rear wheels 15b and the position information of the human-powered vehicle 1. When detecting the vehicle speed in accordance with a change in the position information of the human-powered vehicle 1, the vehicle speed sensor 33 may include, for example, a GPS receiver provided in the human-powered vehicle 1. The GPS receiver is configured to output a signal regarding the current position of the human-powered vehicle 1 to the control unit 31b. The control unit 31b can detect the vehicle speed of the human-powered vehicle 1 based on the signal output from the GPS receiver.

[0055] The cadence sensor 34 is configured to detect the cadence of the human-powered vehicle 1. Cadence is defined, for example, by the number of rotations of the crankshaft 10a per unit time. The unit time is, for example, one minute. The cadence sensor 34 is installed, for example, in the power transmission path from the pedal 10c to the first rotating body 16a. In this embodiment, the cadence sensor 34 is installed on the crank arm 10b.

[0056] The cadence sensor 34 may include, for example, a magnetic sensor that outputs a signal corresponding to the strength of the magnetic field. The cadence sensor 34 may also include an optical sensor, an acceleration sensor, a gyro sensor, or a torque sensor. The cadence sensor 34 may be provided in the drive unit 19.

[0057] The tilt sensor 35 is configured to detect the tilt state of the human-powered vehicle 1. The tilt state is information indicating the degree to which the human-powered vehicle 1 is tilted relative to the horizontal plane when the human-powered vehicle 1 is traveling. The tilt state includes, for example, the pitch angle of the human-powered vehicle 1 and at least one of the gradient of the travel path.

[0058] The tilt sensor 35 may detect the tilt state based, for example, on the acceleration and vehicle speed of the human-powered vehicle 1. The tilt sensor 35 may detect the tilt state based, for example, on the current position of the human-powered vehicle 1. When detecting the tilt state based on the current position of the human-powered vehicle 1, the tilt sensor 35 may include, for example, a GPS receiver provided on the human-powered vehicle 1. The control unit 31b can detect the slope of the road surface on which the human-powered vehicle 1 is traveling based on the signal output from the GPS receiver and the gradient information included in the map information pre-stored in the storage unit 31a.

[0059] The acceleration sensor 36 is configured to detect acceleration in the forward / backward, up / down, and left / right directions. The acceleration sensor 36 includes, for example, three or more axes of acceleration. In this embodiment, the acceleration sensor 36 includes a three-axis acceleration sensor. The acceleration sensor 36 is located in the internal space of the drive unit 19. The acceleration sensor 36 is mounted, for example, on a circuit board for controlling the equipment of the drive unit 19. The arrangement of the acceleration sensor 36 is not limited to this embodiment.

[0060] The rotation sensor 37 is configured to detect the rotational speed of the motor 24 of the drive unit 19. The rotation sensor 37 is located in the internal space of the drive unit 19. The rotation sensor 37 is provided, for example, on the motor output shaft 24a of the motor 24.

[0061] The control unit 31b is configured to communicate with the motor 24 via an electrical cable or a wireless communication device. The control unit 31b is configured to control the motor 24 by outputting a signal to the motor 24. In this embodiment, the control unit 31b is configured to control the motor 24 in a human-powered vehicle 1 that does not have a torque sensor for detecting the human torque input to the human-powered vehicle 1. By not having a torque sensor in the human-powered vehicle 1, the cost of the human-powered vehicle 1 can be reduced. When the motor 24 is driven by the control unit 31b, an assist force is applied to the human-powered vehicle 1.

[0062] The control unit 31b provides assist force to the human-powered vehicle 1 when its speed is below a predetermined speed. In this specification, the upper limit of the vehicle speed at which assist force is provided to the human-powered vehicle 1 is described as the cutoff speed. The cutoff speed is defined, for example, based on a specific law. The cutoff speed may be, for example, 24 km / h. The cutoff speed may be, for example, 45 km / h.

[0063] The control device 31 has multiple control modes for controlling the motor 24. The rider can select one of the multiple modes by operating an operating device provided on the human-powered vehicle 1. The multiple control modes include, for example, a first control mode in which assist force can be applied to the human-powered vehicle 1 when the power to the drive unit 19 is turned on, and a second control mode in which assist force cannot be applied to the human-powered vehicle 1 even when the power to the drive unit 19 is turned on.

[0064] In order to appropriately provide assist force to the human-powered vehicle 1 in the first control mode, the control unit 31b is configured to switch between an assist-permitted state and an assist-disabled state. The assist-permitted state is a state in which the motor 24 of the drive unit 19 is permitted to drive. The control unit 31b switches to the assist-permitted state, for example, when the rider is pedaling. The assist-disabled state is a state in which the motor 24 is prohibited from driving. The control unit 31b switches to the assist-disabled state, for example, when the rider is not pedaling.

[0065] In order to switch between the assist-enabled state and the assist-disabled state, the control unit 31b needs to determine, for example, whether the rider is pedaling or not. Since the human-powered vehicle 1 of this embodiment does not have a torque sensor to detect human torque, the control unit 31b needs to determine whether the rider is pedaling or not without using the value detected by the torque sensor.

[0066] If the control unit 31b were to determine whether or not the rider is pedaling based solely on the cadence of the crank arm 10b, there is a possibility that pedaling may be incorrectly detected. For example, if the crank 10 is turned by hand while the rear wheel 15b is lifted off the ground, pedaling may be incorrectly detected. For example, if a person or other object hits the crank 10 and causes the crank arm 10b to rotate, pedaling may be incorrectly detected.

[0067] The control unit 31b of this embodiment is configured to make it difficult to falsely detect pedaling by determining whether or not pedaling is occurring using cadence and information other than human torque.

[0068] The control unit 31b is configured to control the motor 24 according to the detection result of the cadence of the crank arm 10b of the human-powered vehicle 1 and rotation-related conditions relating to the rotation of the non-driven wheels of the human-powered vehicle 1. For example, the control unit 31b is configured to start applying assist force to the motor 24 according to the detection result of the cadence of the crank arm 10b of the human-powered vehicle 1 and rotation-related information relating to the rotation of the non-driven wheels of the human-powered vehicle 1. In this embodiment, the control unit 31b starts applying assist force by switching from an assist-disabled state to an assist-enabled state.

[0069] Rotation-related information for non-driven wheels is information that changes according to the rotation of the non-driven wheels. Rotation-related information for non-driven wheels includes at least one of the following: vehicle speed information related to the vehicle speed detected by the vehicle speed sensor 33 attached to the non-driven wheel, and distance traveled information related to the distance traveled by the non-driven wheel. The vehicle speed information is, for example, the vehicle speed of the human-powered vehicle 1 according to the wheel speed of the front wheel 15a. The distance traveled information is, for example, the distance traveled by the front wheel 15a according to the amount of rotation of the front wheel 15a. In this embodiment, rotation-related information includes both vehicle speed information and distance traveled information. The control unit 31b switches to an assist-permitted state according to the cadence of the crank arm 10b, the vehicle speed information, and the distance traveled information.

[0070] Figure 4 is used to illustrate an example of the process for switching between the assist-enabled state and the assist-disabled state. Figure 4 is an example of a state transition diagram related to the assist-enabled state and the assist-disabled state.

[0071] When the rider selects the first control mode, the control unit 31b switches between the assist-enabled state and the assist-disabled state according to the state transition diagram in Figure 4. As shown in Figure 4, in the assist-enabled state, the control unit 31b switches to the assist-disabled state when the cadence detected by the cadence sensor 34 falls below a predetermined first threshold. In this embodiment, the first threshold is 5 rpm. The first threshold is not particularly limited as long as it is greater than zero rpm and less than or equal to the second threshold for switching from the assist-disabled state to the assist-enabled state.

[0072] The control unit 31b switches to the assist-enabled state when, in the assist-disabled state, the cadence detected by the cadence sensor 34 is equal to or greater than a predetermined second threshold, and the vehicle speed detected by the vehicle speed sensor 33 is within a predetermined range, and the front wheel 15a continues to travel for 0.1m or more. In this specification, the range of vehicle speed for switching from the assist-disabled state to the assist-enabled state is described as the assist speed range.

[0073] In this embodiment, the second threshold is 5 rpm. The second threshold is not particularly limited as long as it is greater than zero rpm. It is desirable that the second threshold is small enough that assist force is applied to the human-powered vehicle 1 as soon as the rider starts pedaling the pedals 10c.

[0074] In this embodiment, the assist speed range is 1 km / h or more and less than the cutoff speed. The rider can start stable human-powered vehicle 1 by accelerating the vehicle speed of the human-powered vehicle 1 to 3 km / h or more. Since the lower limit of the assist speed range in this embodiment is 1 km / h, the control unit 31b can apply assist force to the human-powered vehicle 1 before it reaches 3 km / h, which is the speed at which stable human-powered vehicle 1 can start.

[0075] By providing assist power to the human-powered vehicle 1 before it reaches a speed of 3 km / h, the control unit 31b makes it easier to accelerate the human-powered vehicle 1 to 3 km / h, for example, when starting on an incline. By making it easier to accelerate the human-powered vehicle 1 to 3 km / h, the control unit 31b makes it easier to drive the human-powered vehicle 1 stably when starting on an incline, thereby improving the comfort of driving when starting on an incline.

[0076] The lower limit of the assist speed range is not particularly limited, as long as it is greater than zero km / h. Ideally, the lower limit of the assist speed range should be less than 3 km / h, which is the speed at which a stable human-powered vehicle 1 can begin to move.

[0077] The control unit 31b determines, for example, whether the front wheel 15a has traveled continuously for 0.1m or more based on the pulse signal from the wheel speed sensor 33a. For example, if the circumference of the front wheel 15a is 2.1m and the total number of slits in the rotating body of the wheel speed sensor 33a is 90, a pulse signal is output when the front wheel 15a has traveled approximately 0.023m. The control unit 31b counts the number of pulse signals when the vehicle speed detected by the vehicle speed sensor 33 is within the assist speed range. The control unit 31b can determine that the front wheel 15a has traveled continuously for 0.1m or more when the number of pulse signals is 5 or more without the vehicle speed exceeding the assist speed range.

[0078] The vehicle speed sensor 33 in this embodiment has relatively high resolution because it detects vehicle speed in response to multiple pulse signals output during one rotation of the front wheel 15a. The high resolution of the vehicle speed sensor 33 means that it is relatively likely to detect a vehicle speed within the assist speed range even when the human-powered vehicle 1 moves slightly forward for reasons other than pedaling. For example, if the rider bumps into the crank 10 and the human-powered vehicle 1 moves a few centimeters, the vehicle speed sensor 33 may detect a vehicle speed within the assist speed range.

[0079] When the vehicle speed within the assist speed range is detected, the control unit 31b maintains the assist-disabled state until the front wheel 15a travels 0.1m. By maintaining the assist-disabled state until the front wheel 15a travels 0.1m, the control unit 31b can prevent unnecessary assist force from being applied to the human-powered vehicle 1 when the human-powered vehicle 1 moves slightly forward for reasons other than pedaling.

[0080] Figure 5 shows a graph with the rotation amount of the crank arm 10b on the vertical axis and the gear ratio on the horizontal axis, illustrating the amount of rotation of the crank arm 10b required for the front wheel 15a to travel 0.1m for each tire circumference. As shown in Figure 5, the amount of rotation of the crank arm 10b required for the front wheel 15a to travel 0.1m decreases as the gear ratio increases.

[0081] With a standard tire circumference and gear ratio, the front wheel 15a travels 0.1m or more before the crank 10 rotates more than 10 degrees. For example, if the tire circumference is 2.1m and the gear ratio is 2, the front wheel 15a travels 0.1m or more when the crank arm 10b rotates approximately 8.6 degrees.

[0082] By setting the threshold for the distance traveled by the front wheel 15a to 0.1m, the control unit 31b switches to the assist-enabled state before the rotation of the crank arm 10b exceeds 10 degrees, under standard tire circumference and gear ratio conditions. By switching to the assist-enabled state before the rotation of the crank arm 10b exceeds 10 degrees, the control unit 31b can quickly provide assist power to the human-powered vehicle 1 after the rider starts pedaling, thereby improving the riding comfort of the human-powered vehicle 1.

[0083] As shown in Figure 5, as the gear ratio increases, the amount of rotation of the crank 10 required for the front wheel 15a to travel 0.1m decreases. Because the amount of rotation of the crank 10 required for the front wheel 15a to travel 0.1m decreases as the gear ratio increases, the control unit 31b can provide assist force to the human-powered vehicle 1 at a relatively early timing when the gear ratio is high. By providing assist force to the human-powered vehicle 1 at a relatively early timing, the control unit 31b can make it easier to start the human-powered vehicle 1 when the gear ratio is high, thereby improving the comfort of riding.

[0084] The threshold for the distance traveled by the front wheel 15a is not limited to this embodiment, as long as it is greater than zero m. It is desirable that the threshold for the distance traveled by the front wheel 15a is small enough that assist force is applied to the human-powered vehicle 1 as quickly as possible after the rider starts pedaling the pedal 10c.

[0085] Figure 6 shows an example of the switching between assist-enabled and assist-disabled states performed by the control unit 31b. The vertical axis in Figure 6(a) represents torque, cadence, and vehicle speed. The horizontal axis in Figure 6(a) represents time. Graph G1 in Figure 6(a) shows an example of human-powered torque input to the pedal 10c. Graph G2 in Figure 6(a) shows an example of cadence detected by the cadence sensor 34. Graph G3 in Figure 6(a) shows an example of vehicle speed detected by the vehicle speed sensor 33. As shown in Figure 6(a), human-powered torque, cadence, and vehicle speed change over time.

[0086] Figure 6(b) shows an example of a pulse signal output by the wheel speed sensor 33a during the same time period as in Figure 6(a). Figure 6(c) shows whether the control unit 31b switched to the assist-enabled state during the same time period as in Figure 6(a). The ON time period shown in Figure 6(c) is the time period when the assist-enabled state was activated. The OFF time period shown in Figure 6(c) is the time period when the assist-disabled state was activated.

[0087] At time T1 shown in Figure 6, the rider presses down on pedal 10c. Between time T1 and time T6 shown in Figure 6, for example, the crank arm 10b rotates one stroke. As shown in Figure 6(a), when the rider presses down on pedal 10c, the human-powered torque increases. When the human-powered torque increases and the human-powered vehicle 1 moves forward, the wheel speed sensor 33a detects the slit.

[0088] As shown in Figure 6(b), the wheel speed sensor 33a detects the slit at time T2, which is after time T1, and outputs a pulse signal. At time T2, the cadence is zero rpm. At time T2, the vehicle speed is zero km / h. The cadence required to switch to the assist-enabled state is 5 rpm or higher. The lower limit of the vehicle speed required to switch to the assist-enabled state is 1 km / h. At time T2, neither the cadence nor the vehicle speed meets the conditions for switching to the assist-enabled state, so as shown in Figure 6(c), the control unit 31b controls the motor 24 in the assist-disabled state.

[0089] Between time T2 and time T3, the human-powered vehicle 1 moves forward further. As the human-powered vehicle 1 moves forward further, the wheel speed sensor 33a detects the slit again and outputs a pulse signal at time T3. The vehicle speed sensor 33 detects a vehicle speed greater than 0 km / h based, for example, on the two most recent times, T2 and T3, when pulse signals were output. For example, at time T3, the vehicle speed sensor 33 detects a vehicle speed of 1 km / h. At time T3, the cadence is 1 rpm. At time T3, the cadence does not meet the conditions for switching to the assist-enabled state, so at time T3 shown in Figure 6(c), the control unit 31b controls the motor 24 in the assist-disabled state.

[0090] Between time T3 and time T4, the human-powered vehicle 1 moves forward further. Between time T3 and time T4, the wheel speed sensor 33a detects the slit five times and outputs a pulse signal five times.

[0091] At time T4, the cadence is 6 rpm. Between time T3 and time T4, the vehicle speed increases from 1 km / h to 3 km / h. Between time T3 and time T4, the distance traveled by the front wheel 15a is approximately 0.115 m. Between time T3 and time T4, the front wheel 15a travels continuously for 0.1 m or more without the vehicle speed exceeding the assist speed range, and the cadence at time T4 is 5 rpm or higher. Therefore, at time T4, the conditions for switching from the assist-disabled state to the assist-enabled state are met. As shown in Figure 6(c), the control unit 31b switches to the assist-enabled state at time T4.

[0092] As shown in Figure 6(a), the manual torque increases between time T1 and time T5. The manual torque decreases between time T5 and time T6. Time T5 is the peak of the manual torque when the crank arm 10b rotates for one stroke.

[0093] In this embodiment, the control unit 31b is switched to the assist-enabled state at time T4, which is before time T5, when the human-powered torque reaches its peak. By switching to the assist-enabled state before the human-powered torque reaches its peak, the control unit 31b can provide assist force to the human-powered vehicle 1 at time T5, when the human-powered torque reaches its peak. Since the assist force is at its maximum when the human-powered torque reaches its peak, the control unit 31b can provide a large assist force to the human-powered vehicle 1 by switching to the assist-enabled state before the human-powered torque reaches its peak, making it easier to drive the human-powered vehicle 1.

[0094] As shown in Figure 1, the rear wheel 15b is connected to the crank 10 via the drive mechanism 16. The rear wheel 15b rotates in conjunction with the rotation of the crank 10. The vehicle speed sensor 33 detects the vehicle speed based on the rotational speed of the front wheel 15a.

[0095] As shown in Figure 4, the control unit 31b can apply assist force to the human-powered vehicle 1 when both the front wheel 15a and the rear wheel 15b are rotating by switching to an assist-permitted state based on the vehicle speed detected by the vehicle speed sensor 33, at least one of the distance traveled by the front wheel 15a, and the cadence. By being able to apply assist force to the human-powered vehicle 1 when both the front wheel 15a and the rear wheel 15b are rotating, the control unit 31b can maintain an assist-disabled state and suppress the application of unnecessary assist force to the human-powered vehicle 1 when the crank 10 is turned by hand while the rear wheel 15b is lifted off the ground.

[0096] The rider may, after stopping the human-powered vehicle 1, move the human-powered vehicle 1 back and forth while sitting on the seat 12. Figure 7 shows an example of switching between the assist-enabled state and the assist-disabled state when the rider moves the human-powered vehicle 1 back and forth while sitting on the seat 12. The vertical axis in Figure 7(a) represents torque and vehicle speed. The horizontal axis in Figure 7(a) represents time. Graph G11 in Figure 7(a) is a graph showing an example of human-powered torque when the rider moves the human-powered vehicle 1 back and forth while sitting on the seat 12. Graph G13 in Figure 7(a) is a graph showing an example of vehicle speed detected by the vehicle speed sensor 33 when the rider moves the human-powered vehicle 1 back and forth while sitting on the seat 12. As shown in Figure 7(a), the human-powered torque and vehicle speed change with the passage of time.

[0097] Figure 7(b) shows an example of a pulse signal output by the wheel speed sensor 33a during the same time period as in Figure 7(a). Figure 7(c) shows whether or not the control unit 31b switched to the assist permission state during the same time period as in Figure 7(a).

[0098] In Figure 7, the rider moves the human-powered vehicle 1 back and forth by applying and releasing force to the pedal 10c while sitting on the seat 12. As shown in Figure 7(a), the human-powered torque pulsates as a result of the rider's operation of the pedal 10c.

[0099] When the rider moves the human-powered vehicle 1 back and forth while seated on the seat 12, the front wheel 15a rotates, and multiple pulse signals may be output, as shown in Figure 7(b). The time intervals between the multiple pulse signals in Figure 7(b) are relatively long. The time intervals between the multiple pulse signals in Figure 7(b) are longer than, for example, the time intervals between pulse signals when the human-powered vehicle 1 is moving by pedaling.

[0100] In Figure 7(b), the time interval between the multiple pulse signals is relatively long, so the vehicle speed shown in Figure 7(a) is less than 1 km / h. For example, the maximum vehicle speed is 0.9 km / h. Since the vehicle speed is outside the assist speed range, as shown in Figure 7(c), the control unit 31b controls the motor 24 in an assist-disabled state, regardless of the cadence.

[0101] If, as shown in Figure 7(a), the vehicle speed falls within the assist speed range, the control unit 31b maintains the assist-disabled state until the state within the assist speed range continues for 0.1m or more. When the rider moves the human-powered vehicle 1 back and forth while seated on the seat 12, it is difficult for the state within the assist speed range to continue for 0.1m or more. Therefore, the control unit 31b can easily maintain the assist-disabled state when the rider moves the human-powered vehicle 1 back and forth while seated on the seat 12. By easily maintaining the assist-disabled state, the control unit 31b can suppress the application of unnecessary assist force to the human-powered vehicle 1 when the rider moves the human-powered vehicle 1 back and forth while seated on the seat 12.

[0102] When the rider moves the human-powered vehicle 1 back and forth while seated on the seat 12, the vehicle speed sensor 33 may detect a higher vehicle speed than the actual speed based on the slit detected by the wheel speed sensor 33a. For example, the vehicle speed sensor 33 may detect a vehicle speed higher than the cutoff vehicle speed. The control unit 31b maintains the assist-disabled state when the vehicle speed detected by the vehicle speed sensor 33 is higher than the cutoff vehicle speed, thereby suppressing the application of unnecessary assist force to the human-powered vehicle 1 when the vehicle speed sensor 33 detects a higher vehicle speed than the actual speed.

[0103] In this embodiment, the control unit 31b can appropriately switch between the assist-enabled state and the assist-disabled state without using the torque sensor's detected value. By appropriately switching between the assist-enabled state and the assist-disabled state without using the torque sensor's detected value, the motor 24 of the drive unit 19 can be appropriately controlled even if the human-powered vehicle 1 is not equipped with a torque sensor.

[0104] The procedure for determining the assist force is explained. In the explanation of the procedure for determining the assist force, the assist force may be described as assist torque. Figure 8 is used to explain the procedure for determining the assist torque in a typical drive unit. The sensor detection values ​​shown in Figure 8 are the human torque, vehicle speed, and cadence detected by the torque sensor, vehicle speed sensor, and cadence sensor installed in the human-powered vehicle.

[0105] In a typical drive unit, the assist torque is determined according to the human torque detected by the torque sensor and a predetermined assist ratio. The assist ratio is a parameter that defines the magnitude of the assist torque relative to the human torque. The assist torque is determined, for example, by the product of the human torque and the assist ratio.

[0106] In a typical drive unit, once the assist torque is determined, a low-pass filter is applied to the assist torque. After the low-pass filter is applied to the assist torque, it is determined whether the vehicle speed detected by the vehicle speed sensor and the cadence detected by the cadence sensor are below predetermined limits. In Figure 8, it is determined whether the vehicle speed is below the limit, and then whether the cadence is below the limit. The limit for vehicle speed is, for example, equal to the cutoff vehicle speed.

[0107] In a typical drive unit, the motor is controlled according to the determined assist torque, the vehicle speed, and the cadence. For example, if both the vehicle speed and cadence are below the limit, a command value corresponding to the assist torque after applying a low-pass filter is output to the motor, and the assist torque after applying the low-pass filter is applied to the human-powered vehicle. For example, if at least one of the vehicle speed and cadence is above the limit, a command value prohibiting the output of assist torque is output to the motor, and the application of assist torque to the human-powered vehicle is prohibited.

[0108] Figures 4 and 9 are used to illustrate the procedure for determining the assist torque in the drive unit 19 of this embodiment. The control unit 31b starts applying assist force by switching to the assist permission state shown in Figure 4. Once the application of assist force is started, the control unit 31b is configured to control the motor 24 according to the driving information and driving resistance information of the human-powered vehicle 1.

[0109] In this embodiment, since the human-powered vehicle 1 is not equipped with a torque sensor, the control unit 31b determines the assist force according to the driving information and driving resistance information of the human-powered vehicle 1, without using the detected value of the torque sensor that detects the human-powered torque input to the human-powered vehicle 1.

[0110] The driving information shown in Figure 9 indicates the state in which the human-powered vehicle 1 is being driven. For example, the driving information includes at least one of the vehicle speed, wheel speed, and cadence of the human-powered vehicle 1. In this embodiment, the driving information includes vehicle speed and cadence. The driving information further includes the acceleration at the start of pedaling and the slope of the road surface. The acceleration at the start of pedaling and the slope of the road surface are used by the control unit 31b to determine the assist torque when the pedal 10c is pedaled. The procedure for determining the assist torque when the pedal 10c is pedaled will be described later.

[0111] The running resistance information indicates what kind of resistance is acting on the human-powered vehicle 1. For example, the running resistance information includes at least one of acceleration resistance, gradient resistance, and rolling resistance. In this embodiment, the running resistance information includes acceleration resistance, gradient resistance, and rolling resistance. The running resistance information may include information other than acceleration resistance, gradient resistance, and rolling resistance. For example, the running resistance information may include air resistance.

[0112] In this embodiment, the control unit 31b calculates the total torque based on the driving information and the driving resistance information. The total torque is the sum of the assist torque and the human-powered torque. After calculating the total torque, the control unit 31b distributes the total torque between the human-powered torque and the assist torque using the assist ratio. By distributing the total torque, the control unit 31b can determine the assist torque to be applied to the human-powered vehicle 1 at the time of total torque calculation from the driving resistance information and the driving information. The control unit 31b then applies the determined assist force to the human-powered vehicle 1.

[0113] By determining the assist torque from the driving resistance information and driving information, the control unit 31b can determine the assist torque without using the torque sensor's detected value. Because the assist torque can be determined without using the torque sensor's detected value, the control unit 31b can appropriately control the motor 24 of the drive unit 19 even if the human-powered vehicle 1 is not equipped with a torque sensor. Because the control unit 31b can appropriately control the motor 24 even if the human-powered vehicle 1 is not equipped with a torque sensor, the cost required to determine the assist torque can be reduced. For example, the control unit 31b can omit the torque sensor, thereby reducing costs.

[0114] An example of a procedure for determining the assist torque is described. Figure 10 shows an example of a motor control flow for determining the assist torque and controlling the motor 24. Figure 11 shows the flow of various information used in the motor control flow. The symbols shown in Figure 11 correspond to the steps of the motor control flow shown in Figure 10. For example, the symbol S2 for acceleration resistance shown in Figure 11 means that the acceleration resistance is calculated in step S2 shown in Figure 10.

[0115] The control unit 31b starts the motor control flow when predetermined conditions are met. For example, the control unit 31b starts the motor control flow when it switches to the assist-enabled state shown in Figure 4. When the motor control flow ends, the control unit 31b repeatedly executes the motor control flow at predetermined intervals until predetermined conditions are met. In this embodiment, the control unit 31b repeatedly executes the motor control flow until it switches to the assist-disabled state.

[0116] As shown in Figure 10, in step S1, the control unit 31b acquires detection values ​​from various sensors via the detection unit 32. For example, the control unit 31b acquires the vehicle speed, cadence, incline, acceleration, and rotational speed of the motor 24 of the human-powered vehicle 1. After performing the processing in step S1, the control unit 31b proceeds to step S2.

[0117] In step S2 shown in Figures 10 and 11, the control unit 31b calculates the acceleration resistance using the detected value acquired in step S1. The acceleration resistance is the resistance generated when the human-powered vehicle 1 accelerates. The acceleration resistance is proportional to the weight of the human-powered vehicle 1 and the acceleration. The weight of the human-powered vehicle 1 is, for example, the total weight of the human-powered vehicle 1 and the rider. In this embodiment, the weight of the human-powered vehicle 1 is set in advance. The weight of the human-powered vehicle 1 is stored in the storage unit 31a of the control device 31. In Figure 11, the variables stored in the storage unit 31a are shown as assist setting values.

[0118] The weight of the human-powered vehicle 1 may change, for example, according to the weight of the rider detected by a weight sensor installed on the human-powered vehicle 1. If the weight of the human-powered vehicle 1 is M and the acceleration of the human-powered vehicle 1 is a, then the acceleration resistance F a This is expressed by the following equation 1. (Formula 1)F a [N] = M [kg] × a [m / s] 2 ]

[0119] Figure 12 shows an example of a subflow of step S2, in which the acceleration resistance is calculated using Equation 1. The subflow of Figure 12 will be described later. As shown in Figure 10, after performing the processing in step S2, the control unit 31b proceeds to step S3.

[0120] In step S3 shown in Figures 10 and 11, the control unit 31b calculates the gradient resistance using the detected value acquired in step S1. Figure 13 schematically shows a road surface inclined at an angle θ with respect to the horizontal plane. Gradient resistance is the force acting in the opposite direction to the direction of travel of the human-powered vehicle 1 when the human-powered vehicle 1 travels along the road surface. If the weight of the human-powered vehicle 1 is M and the inclination with respect to the road surface is θ, then the gradient resistance F g This is expressed by the following equation 2. (Formula 2)F g [N] = M [kg] × g [m / s] 2 ]×sinθ[rad]

[0121] FIG. 14 shows an example of a sub-flow of step S3 for calculating gradient resistance using Equation 2. The sub-flow in FIG. 14 will be described later. As shown in FIG. 10, the control unit 31b proceeds to step S4 after performing the process of step S3.

[0122] In step S4 shown in FIG. 10 and FIG. 11, the control unit 31b calculates rolling resistance using the detection value acquired in step S1. The rolling resistance is a resistance generated when a tire rolls on a road surface. When the weight of the human-powered vehicle 1 is M, the gravitational acceleration is g, and the rolling resistance coefficient is μ, the rolling resistance F r is represented by Equation 3 below. (Equation 3) F r [N] = M [kg] × g [m / s 2 × μ [-]

[0123] The gravitational acceleration and the rolling resistance coefficient are set in advance. The gravitational acceleration and the rolling resistance coefficient are stored in, for example, the storage unit 31a of the control device 31. By substituting the weight of the human-powered vehicle 1, the gravitational acceleration, and the rolling resistance coefficient stored in the storage unit 31a into Equation 3, the control unit 31b can perform a rolling resistance determination process that determines the rolling resistance based on the weight of the human-powered vehicle 1 and the friction coefficient of the road surface on which the human-powered vehicle 1 travels. The control unit 31b proceeds to step S5 after performing the process of step S4.

[0124] In step S5, the control unit 31b calculates the total torque using the detection value acquired in step S1, and the acceleration resistance, gradient resistance, and rolling resistance calculated in steps S2 to S4. FIG. 15 shows an example of a sub-flow of step S5 for calculating the total torque. The sub-flow in FIG. 15 will be described later. As shown in FIG. 10 and FIG. 11, the control unit 31b proceeds to step S6 after performing the process of step S5.

[0125] In step S6, the control unit 31b distributes the total torque calculated in step S5 into human torque and assist torque. By distributing the total torque, the control unit 31b can calculate the assist torque from the total torque. An example of the process for calculating the assist torque is described below.

[0126] Human torque T h And the assist torque is T a In that case, the total torque T t This is expressed by equation 4 below. (Formula 4)T t [Nm]=T h [Nm]+T a [Nm]

[0127] Human torque T h If the assist ratio is set to AR, the assist torque T a This is expressed by equation 5 below. (Formula 5)T a [Nm]=T h [Nm]×AR

[0128] Assist torque T in Equation 4 a The assist torque T of formula 5 a Substituting this, the total torque T t This is expressed by equation 6 below. (Formula 6)T t [Nm]=T h [Nm]+T h [Nm] × AR = T h [Nm] × (1 + AR)

[0129] Rearranging equation 6 gives the manual torque T. h This is expressed by the following equation 7. (Formula 7)T h [Nm]=T t [Nm] / (1+AR)

[0130] Manual torque T in Equation 7 h The human torque T in Equation 5 h Substituting this into the equation and simplifying, we get the assist torque T. a The total torque is Tt This can be expressed by the following equation 8, where AR is the assist ratio. (Formula 8)T a [Nm]=T t [Nm] × (AR / (1 + AR))

[0131] The assist ratio is stored in the memory unit 31a. In step S6, the control unit 31b calculates the total torque calculated in step S5 as the total torque T in Equation 8. t The assist torque is calculated in reverse from the total torque by substituting the assist ratio stored in the memory unit 31a into the assist ratio AR in equation 8. After performing the processing in step S6, the control unit 31b proceeds to step S7.

[0132] In step S7, the control unit 31b determines the assist torque. When pedaling is in progress, the control unit 31b determines the assist torque calculated in step S6 as the assist torque to be applied to the human-powered vehicle 1. When the rider starts to pedal the pedal 10c, the control unit 31b determines the assist torque calculated based on a predetermined reference assist torque and the assist torque calculated in step S6 as the assist torque to be applied to the human-powered vehicle 1 when starting to pedal.

[0133] The predetermined reference assist torque is the assist torque that allows the human-powered vehicle 1 to accelerate by a predetermined acceleration when the rider starts pedaling the pedal 10c. The predetermined reference assist torque is greater than, for example, the assist torque calculated in step S6. In this specification, the predetermined reference assist torque may be described as the predetermined reference assist force.

[0134] The predetermined reference assist torque changes depending on the state of the human-powered vehicle 1. For example, the predetermined reference assist torque when the human-powered vehicle 1 is traveling on a flat road surface is smaller than the predetermined reference assist torque when the human-powered vehicle 1 is traveling uphill. Since the predetermined reference assist torque changes depending on the state of the human-powered vehicle 1, the control unit 31b is configured to update the predetermined reference assist torque. Figure 19 shows an example of a torque update flow for updating the predetermined reference assist torque. The torque update flow in Figure 19 and the process for determining the assist torque in step S7 will be described later. As shown in Figures 10 and 11, after performing the process in step S7, the control unit 31b proceeds to step S8.

[0135] In steps S8 and S9, the control unit 31b controls the motor 24 according to the vehicle speed and cadence, similar to the control of a typical drive unit shown in Figure 8.

[0136] For example, if the vehicle speed acquired in step S1 is less than the cutoff vehicle speed and the cadence acquired in step S1 is less than a predetermined threshold, the control unit 31b controls the motor 24 to apply the assist torque determined in step S7 to the human-powered vehicle 1. For example, if the vehicle speed acquired in step S1 is greater than or equal to the cutoff vehicle speed and at least one of the following conditions is met, the control unit 31b controls the motor 24 to prohibit the output of the assist torque. After performing the processing in step S9, the control unit 31b terminates the motor control flow.

[0137] Figures 10 to 16 are used to explain the subflows of the motor control flow. The subflows include an acceleration resistance subflow for calculating the acceleration resistance in step S2, a gradient resistance subflow for calculating the gradient resistance in step S3, and a total torque subflow for calculating the total torque in step S5.

[0138] Figures 10 to 12 are used to explain the acceleration resistance subflow. When the control unit 31b calculates the acceleration resistance in step S2 shown in Figures 10 and 11, it proceeds to step S11 of the acceleration resistance subflow shown in Figure 12.

[0139] In step S11, the control unit 31b calculates the acceleration of the human-powered vehicle 1 in the direction of travel by differentiating the vehicle speed obtained in step S1 shown in Figure 10. In this embodiment, the unit of acceleration calculated by the control unit 31b is G. When the human-powered vehicle 1 is accelerating, the acceleration is a positive value. When the human-powered vehicle 1 is decelerating, the acceleration is a negative value. The control unit 31b clips the calculated acceleration within a predetermined range. The predetermined range may be, for example, from zero G to 0.5 G.

[0140] In step S11, if the calculated acceleration is a negative value, the control unit 31b corrects the acceleration to zero G. If the calculated acceleration is greater than 0.5 G, the control unit 31b corrects the acceleration to 0.5 G. If the calculated acceleration is within the range of zero G to 0.5 G, the control unit 31b does not correct the acceleration.

[0141] If the rider stops the human-powered vehicle 1 and then moves it back and forth slightly, a higher vehicle speed than the actual speed may be detected. When a higher vehicle speed than the actual speed is detected, the acceleration calculated by the control unit 31b may be greater than 0.5G. By clipping the acceleration in step S11, the control unit 31b can suppress the acceleration from becoming excessively large when a higher vehicle speed than the actual speed is detected. As shown in Figure 12, after processing in step S11, the control unit 31b proceeds to step S12.

[0142] The unit of acceleration 'a' in Equation 1 for calculating acceleration resistance is m / s². 2 Therefore, in step S12, the control unit 31b converts the acceleration clipped in step S11 from G to m / s². 2Convert to [value]. After performing the processing in step S12, the control unit 31b proceeds to step S13.

[0143] In step S13, if the cadence obtained in step S1 shown in Figure 10 is greater than 5 rpm, the control unit 31b proceeds to step S14 shown in Figure 12. If the cadence is 5 rpm or less, the control unit 31b proceeds to step S15.

[0144] In step S14, the control unit 31b performs an acceleration resistance determination process to determine the acceleration resistance based on the weight of the human-powered vehicle 1 and the acceleration in the direction of travel. In this embodiment, the control unit 31b calculates the acceleration resistance by substituting the weight of the human-powered vehicle 1 stored in the memory unit 31a and the acceleration converted in step S12 into equation 1. After performing the processing in step S14, the control unit 31b terminates the acceleration resistance subflow.

[0145] In step S15, the control unit 31b sets the acceleration resistance to zero N. In this embodiment, the assist torque is calculated inversely from the total torque. The total torque decreases as the acceleration resistance decreases. By setting the acceleration resistance to zero N, the control unit 31b reduces the total torque and weakens the assist torque. After performing the processing in step S15, the control unit 31b terminates the acceleration resistance subflow.

[0146] By executing the acceleration resistance subflow, the control unit 31b can perform acceleration resistance determination processing in at least one of the following cases: when the cadence of the crank arm 10b of the human-powered vehicle 1 is greater than a predetermined threshold, and when a predetermined time has elapsed since the rotation of the crank arm 10b of the human-powered vehicle 1 was detected. In this embodiment, the control unit 31b can proceed to step S14 and perform acceleration resistance determination processing when the cadence of the crank arm 10b is greater than 5 rpm. The predetermined threshold is not limited to this embodiment, as long as it is greater than zero rpm.

[0147] When the human-powered vehicle 1 is traveling downhill, it is assumed that pedaling will stop and the cadence of the crank arm 10b will be 5 rpm or less. The control unit 31b sets the acceleration resistance to zero N when the cadence is 5 rpm or less. By setting the acceleration resistance to zero N, the control unit 31b can reduce the assist torque when the human-powered vehicle 1 accelerates while pedaling is stopped, thereby preventing excessive assist torque from being applied to the human-powered vehicle 1.

[0148] The control unit 31b may perform acceleration resistance determination processing when conditions different from those in this embodiment are met. For example, the control unit 31b may perform acceleration resistance determination processing when a predetermined time has elapsed since detecting the rotation of the crank arm 10b. For example, the control unit 31b may perform acceleration resistance determination processing when the cadence of the crank arm 10b is greater than a predetermined threshold and a predetermined time has elapsed since detecting the rotation of the crank arm 10b. The control unit 31b can detect the rotation of the crank arm 10b based on the cadence detected by the cadence sensor 34, for example. The control unit 31b can detect the rotation of the crank arm 10b when the cadence detected by the cadence sensor 34 becomes greater than zero rpm.

[0149] Figures 10, 11, and 14 are used to illustrate the gradient resistance subflow for calculating the gradient resistance. When the control unit 31b calculates the gradient resistance in step S3 shown in Figures 10 and 11, it proceeds to step S21 of the gradient resistance subflow shown in Figure 14.

[0150] In step S21, the control unit 31b clips the gradient acquired in step S1 shown in Figure 10 to a predetermined range. The predetermined range may be, for example, from 0% to 15%. The gradient is a positive value when the human-powered vehicle 1 is traveling uphill. The gradient is a negative value when the human-powered vehicle 1 is traveling downhill. If the gradient is a negative value, the control unit 31b corrects the gradient to 0%. If the gradient is greater than 15%, the control unit 31b corrects the gradient to 15%. As shown in Figure 14, after performing the processing in step S21, the control unit 31b proceeds to step S22.

[0151] In Equation 2 for calculating gradient resistance, the slope is expressed in the form of sinθ. Therefore, in step S22, the control unit 31b converts the slope clipped in step S21 into sinθ. After performing the processing in step S22, the control unit 31b proceeds to step S23.

[0152] In step S23, if the cadence obtained in step S1 shown in Figure 10 is greater than 5 rpm, the control unit 31b proceeds to step S24 shown in Figure 14. If the cadence is 5 rpm or less, the control unit 31b proceeds to step S25.

[0153] In step S24, the control unit 31b performs a gradient resistance determination process to determine the gradient resistance based on the weight of the human-powered vehicle 1 and the incline of the road surface on which the human-powered vehicle 1 travels. In this embodiment, the control unit 31b calculates the gradient resistance by substituting the weight of the human-powered vehicle 1 stored in the storage unit 31a and the incline converted in step S22 into equation 2. After performing the processing in step S24, the control unit 31b proceeds to step S26.

[0154] In step S25, the control unit 31b sets the gradient resistance to zero N. In this embodiment, the assist torque is calculated inversely from the total torque. The total torque decreases as the gradient resistance decreases. By setting the gradient resistance to zero N, the control unit 31b reduces the total torque and weakens the assist torque. After performing the processing in step S25, the control unit 31b proceeds to step S26.

[0155] In step S26, the control unit 31b applies a gradient resistance change limiter and corrects the gradient resistance obtained in step S24 or step S25. The gradient resistance change limiter is an upper limit set for the gradient resistance to prevent the amount of change in the gradient resistance from becoming excessively large. The control unit 31b corrects the gradient resistance so that the amount of change in the gradient resistance during a predetermined limit period falls within a predetermined upper limit. The limit period is, for example, the period from the present to 1 second ago. The predetermined upper limit is, for example, 50N.

[0156] For example, if the gradient resistance calculated in step S24 is 60N and the gradient resistance calculated 1 second ago was 5N, the change in gradient resistance will be 55N, so the control unit 31b corrects the gradient resistance so that the change becomes 50N. For example, the control unit 31b corrects the gradient resistance from 60N to 55N. The parameters of the change amount limiter are not particularly limited. For example, the limit period may be a different period from the period from the present to 1 second ago. For example, the predetermined upper limit may be a different value from 50N. After performing the processing in step S25, the control unit 31b terminates the gradient resistance subflow.

[0157] By executing the gradient resistance subflow, the control unit 31b can perform gradient resistance determination processing in at least one of the following cases: when the cadence of the crank arm 10b of the human-powered vehicle 1 is greater than a predetermined threshold, and when a predetermined time has elapsed since the rotation of the crank arm 10b of the human-powered vehicle 1 was detected. In this embodiment, if the cadence of the crank arm 10b is greater than 5 rpm, the process can proceed to step S24 to perform gradient resistance determination processing. The predetermined threshold is not limited to this embodiment, as long as it is greater than zero rpm.

[0158] The control unit 31b sets the gradient resistance to zero Nm when the cadence is 5 rpm or less. For example, the control unit 31b sets the gradient resistance to zero Nm when the pedal 10c is operated while the human-powered vehicle 1 is placed on a stand for maintenance or other purposes. By setting the gradient resistance to zero Nm, the control unit 31b can prevent excessive assist torque from being applied to the human-powered vehicle 1 when the pedal 10c is operated for maintenance or other purposes.

[0159] The control unit 31b may perform gradient resistance determination processing when conditions different from those in this embodiment are met. For example, the control unit 31b may perform gradient resistance determination processing when a predetermined time has elapsed since detecting the rotation of the crank arm 10b. For example, the control unit 31b may perform gradient resistance determination processing when the cadence of the crank arm 10b is greater than a predetermined threshold and a predetermined time has elapsed since detecting the rotation of the crank arm 10b.

[0160] Figures 2, 10, 11, and 15 are used to explain the total torque subflow for calculating the total torque. In the explanation of the total torque subflow, the total torque during the calculation is indicated as a provisional total torque value. When the control unit 31b calculates the total torque in step S5 shown in Figures 10 and 11, it proceeds to step S31 of the total torque subflow shown in Figure 15.

[0161] In step S31, if the vehicle speed acquired in step S1 shown in Figure 10 is greater than zero km / h and the cadence is greater than 20 rpm, the control unit 31b proceeds to step S33 shown in Figure 15. If the vehicle speed is zero km / h or less and the cadence is 20 rpm or less, the control unit 31b proceeds to step S32. The threshold used in step S31 is not limited to this embodiment as long as it is greater than zero.

[0162] In step S32, the control unit 31b sets the provisional total torque value to zero Nm. By setting the provisional total torque value to zero Nm, the control unit 31b reduces the total torque and weakens the assist torque. After performing the process in step S32, the control unit 31b proceeds to step S34.

[0163] In step S33, the control unit 31b calculates a provisional total torque value using the running resistance information and the human power. In this embodiment, the running resistance information includes acceleration resistance, gradient resistance, and rolling resistance, so the acceleration resistance is F a Let the gradient resistance be F. g And the rolling resistance is F r In this case, the running resistance F t This is expressed by the following equation 9. (Formula 9)F t [N]=F a [N]+F g [N]+F r [N]

[0164] The control unit 31b calculates the running resistance in step S2 shown in Figure 10 using the formula F in equation 9. a Substitute this into the equation, and the gradient resistance calculated in step S3 is given by F in equation 9. g Substitute this into the equation, and the rolling resistance calculated in step S4 is given by F in equation 9. r By substituting these values, the running resistance can be calculated.

[0165] Driving resistance F t Assuming the vehicle speed is S, the human power P is expressed by the following equation 10. (Formula 10)P[W]=F t [N] × S [m / s]

[0166] Total torque T t Assuming that cadence is C and pi is π, the human power P is expressed by the following equation 11. (Formula 11)P[W]=T t [Nm] × C [rpm] × (2π / 60)

[0167] Rearranging equation 11 gives the total torque T. t This is expressed by the following equation 12. (Formula 12)T t [Nm] = P[W] ÷ C[rpm] × (60 / 2π)

[0168] Substituting the human power P from Equation 10 into the human power P in Equation 12, we get the total torque T. t The running resistance is F t It can be expressed by the following equation 13, where S is the vehicle speed, C is the cadence, and π is the value of pi. (Formula 13)T t [Nm]=F t [N] × S [m / s] ÷ C [rpm] × (60 / 2π)

[0169] In step S33, the control unit 31b calculates a provisional total torque value using equation 13. The control unit 31b then uses the running resistance calculated using equation 9 to calculate the running resistance F in equation 13. t The total provisional torque value is calculated by substituting the vehicle speed obtained in step S1 into the vehicle speed S in equation 13, and the cadence obtained in step S1 into the cadence C in equation 13. As shown in Figure 15, after performing the processing in step S33, the control unit 31b proceeds to step S34.

[0170] In step S34, the control unit 31b proceeds to step S35 shown in Figure 15 if at least one of the following conditions is met: the cadence has decreased, and the first one-way clutch 23 shown in Figure 2 is in a clutch-disengaged state. The control unit 31b proceeds to step S36 if both of the following conditions are met: the cadence has not decreased, and the first one-way clutch 23 is not in a clutch-disengaged state.

[0171] As shown in Figure 11, the control unit 31b performs a cadence decrease determination process to determine whether the cadence has decreased, separately from the processing in step S5 corresponding to the total torque subflow. The control unit 31b repeats the cadence decrease determination process at predetermined time intervals. Based on the determination value of the cadence decrease determination process, the control unit 31b determines in step S34 whether the cadence has decreased. An example of the cadence decrease determination process is described below.

[0172] In the cadence decrease detection process, the control unit 31b calculates the change in cadence by subtracting the past cadence from the current cadence detected by the cadence sensor 34. The past cadence is, for example, the cadence from 10 ms ago. The control unit 31b determines that the cadence has decreased if, for example, the change in cadence is smaller than a predetermined threshold and the current cadence is greater than zero rpm. The predetermined threshold is, for example, -0.5 rpm.

[0173] After determining that the cadence has decreased, the control unit 31b determines that the cadence has not decreased if a predetermined condition is met. For example, the control unit 31b determines that the cadence has not decreased if at least one of the following conditions is met: the current cadence is equal to a predetermined threshold, or the amount of change in cadence is greater than a predetermined threshold. The predetermined threshold is, for example, zero rpm.

[0174] The control unit 31b performs an engagement state determination flow to determine whether the first one-way clutch 23 is in a clutch-disengaged state, separate from the processing in step S5 which corresponds to the total torque subflow. Based on the determination value of the engagement state determination flow, the control unit 31b determines in step S34 whether the first one-way clutch 23 is in a clutch-disengaged state. Figure 17 shows an example of the engagement state determination flow. The clutch-disengaged state and the engagement state determination flow will be described later.

[0175] In step S35 of Figure 15, which is triggered when the cadence decreases and at least one of the following conditions is met: the first one-way clutch 23 is in a clutch-disengaged state, the control unit 31b sets the provisional total torque value to zero Nm. After performing the processing in step S35, the control unit 31b proceeds to step S36.

[0176] In step S36, the control unit 31b calculates a provisional total torque value by applying a low-pass filter to the provisional total torque value. After performing the processing in step S36, the control unit 31b terminates the total torque subflow. In this specification, the final total torque calculated in the total torque subflow is described as the calculated total torque value.

[0177] The control unit 31b can obtain a total torque calculation value using running resistance calculated without considering air resistance by performing a total torque subflow. For example, the control unit 31b can obtain a total torque calculation value using the sum of acceleration resistance, gradient resistance, and rolling resistance. The control unit 31b calculates acceleration resistance, gradient resistance, and rolling resistance using common parameters. For example, the control unit 31b calculates acceleration resistance, gradient resistance, and rolling resistance using the weight of a common human-powered vehicle 1.

[0178] Air resistance is calculated using parameters different from acceleration resistance, gradient resistance, and rolling resistance. For example, air resistance is calculated using the frontal projected area and the drag coefficient. The control unit 31b can reduce the number of parameters required to calculate running resistance by calculating running resistance without considering air resistance.

[0179] In this embodiment, the control unit 31b applies assist torque when the vehicle speed of the human-powered vehicle 1 is low. For example, the control unit 31b applies assist torque to the human-powered vehicle 1 when its vehicle speed is below the cutoff speed. Since air resistance is low when the vehicle speed of the human-powered vehicle 1 is low, the control unit 31b is less affected by the calculation of running resistance without considering air resistance.

[0180] Figure 16 is used to illustrate a specific example of the total torque subflow. The vertical axis in Figure 16(a) represents torque. The vertical axis in Figure 16(b) represents cadence. The horizontal axis in Figures 16(a) and 16(b) represents time. Graph G21 in Figure 16(a) is a graph showing an example of the calculated total torque value. Graph G22 in Figure 16(a) is a graph showing an example of the provisional total torque value before the low-pass filter is applied in step S36 shown in Figure 15. Graph G23 in Figure 16(a) is a graph showing an example of the provisional total torque value calculated in step S33 shown in Figure 15. Figure 16(b) shows an example of cadence for the same time period as in Figure 16(a). As shown in Figure 16, the calculated total torque value, the provisional total torque value, and the cadence change over time.

[0181] In Figure 16(b), the cadence is higher than 20 rpm in the time period before time T23. In Figure 16(b), the cadence decreases to 20 rpm between time T21 (before time T23) and time T23. The cadence decreases to zero rpm in the time period after time T23.

[0182] The provisional total torque values ​​shown in graphs G22 and G23 of Figure 16(a) are calculated by dividing the vehicle speed, etc., by the cadence. The control unit 31b calculates the provisional total torque value when the cadence is greater than 20 rpm in the total torque subflow shown in Figure 15, thus preventing the vehicle speed, etc., from being divided by zero.

[0183] Since the provisional total torque is calculated by dividing the vehicle speed by the cadence, the provisional total torque increases as the cadence decreases. For example, as shown in graph G23 of Figure 16(a), the provisional total torque jumps up between time T22 and time T23, when the cadence approaches zero rpm.

[0184] For example, when a rider stops pedaling, the cadence approaches zero rpm. When a rider stops pedaling, the actual total torque is considered to be relatively low. When the cadence decreases in the total torque subflow shown in Figure 15, the control unit 31b sets the provisional total torque to zero Nm through the processing in steps S34 and S35. For example, as shown in graph G22 in Figure 16(a), the control unit 31b sets the provisional total torque to zero Nm at time T22, before the cadence decreases to 20 rpm. By setting the provisional total torque to zero Nm at time T22, the control unit 31b can reduce the assist force when the cadence drops sharply.

[0185] By reducing the assist force when the cadence drops sharply, the control unit 31b can suppress a spike in the hypothetical total torque value when the actual total torque is considered to be relatively low, such as when the rider stops pedaling. By suppressing the spike in the hypothetical total torque value, the control unit 31b can appropriately control the assist force and improve riding comfort.

[0186] As shown in graph G21 in Figure 16(a), the control unit 31b applies a low-pass filter to the assumed total torque value. By applying the low-pass filter, the control unit 31b can gradually decrease the calculated total torque value after setting the assumed total torque value to zero Nm. For example, if the control unit 31b sets the assumed total torque value to zero Nm at time T22 as shown in Figure 16(a), it can gradually decrease the calculated total torque value from time T22 to time T24. By gradually decreasing the calculated total torque value, the control unit 31b can suppress a sudden drop in assist torque, thereby improving driving comfort.

[0187] Figures 1 and 2 are used to illustrate the clutch disengaged state of the first one-way clutch 23. The human-powered vehicle 1 is provided with a one-way clutch located in the power transmission path from the crankshaft 10a to the front sprocket 16d. The clutch has a clutch engaged state in which power is transmitted from the crankshaft 10a to the front sprocket 16d when the crankshaft 10a rotates in a first rotational direction, and a clutch disengaged state in which power is not transmitted from the crankshaft 10a to the front sprocket 16d when the crankshaft 10a rotates in a second rotational direction opposite to the first rotational direction. In this embodiment, the one-way clutch includes the first one-way clutch 23 shown in Figure 2. In this specification, the first one-way clutch 23 may be referred to as the one-way clutch.

[0188] The first one-way clutch 23 is provided to connect the output shaft 21, which is located in the power transmission path from the motor 24 to the front sprocket 16d, with the transmission shaft 22, which rotates in conjunction with the rotation of the crankshaft 10a. When the transmission shaft 22 rotates in the first rotational direction in which the human-powered vehicle 1 moves forward as the crankshaft 10a rotates, the first one-way clutch 23 engages with the transmission shaft 22 and the output shaft 21. In this embodiment, the state in which the first one-way clutch 23 engages with the transmission shaft 22 and the output shaft 21 is called the clutch engaged state. In the clutch engaged state, the transmission shaft 22 and the output shaft 21 rotate together, so power is transmitted from the crankshaft 10a to the front sprocket 16d.

[0189] When the transmission shaft 22 rotates in the second rotational direction, causing the human-powered vehicle 1 to move backward, as the crankshaft 10a rotates, the first one-way clutch 23 does not engage with the transmission shaft 22 and the output shaft 21. In this embodiment, the state in which the first one-way clutch 23 does not engage with the transmission shaft 22 and the output shaft 21 is called the clutch disengaged state. In the clutch disengaged state, the transmission shaft 22 rotates relative to the output shaft 21, so power is not transmitted from the crankshaft 10a to the front sprocket 16d.

[0190] When the motor 24 is driven, power is transmitted to the output shaft 21, and the output shaft 21 can rotate. If the rotational speed of the output shaft 21 due to the driving of the motor 24 is faster than the rotational speed of the crank shaft 10a due to pedaling, the first one-way clutch 23 becomes disengaged, and the crank shaft 10a and the front sprocket 16d rotate relative to each other. When the crank shaft 10a and the front sprocket 16d rotate relative to each other, the pedal 10c is light, and the human torque is relatively small. In step S34 shown in Figure 15, if the first one-way clutch 23 is disengaged, the control unit 31b proceeds to step S36 and sets the provisional total torque value to zero Nm.

[0191] In steps S34 and S35, the control unit 31b reduces the assist force when the one-way clutch is disengaged. By reducing the assist force when the clutch is disengaged, the control unit 31b can weaken the assist torque when the pedal 10c is light. By weakening the assist torque when the pedal 10c is light, the control unit 31b can prevent excessive assist torque from being applied to the human-powered vehicle 1.

[0192] Figures 2, 11, and 17 are used to illustrate the engagement state determination flow for determining whether or not the clutch is disengaged. As shown in Figure 11, the control unit 31b performs the engagement state determination flow separately from the processing in step S5, which corresponds to the total torque subflow for calculating the total torque. For example, the control unit 31b repeats the engagement state determination flow at predetermined time intervals. As shown in Figure 17, when the control unit 31b starts the engagement state determination flow, it proceeds to step S41.

[0193] In step S41, if the converted speed is less than a predetermined threshold, the control unit 31b proceeds to step S42. If the converted speed is greater than or equal to a predetermined threshold, the control unit 31b proceeds to step S43. The predetermined threshold is 20 rpm. The predetermined threshold is not limited to this embodiment, as long as it is greater than zero rpm.

[0194] The converted speed is the speed obtained by converting the rotational speed of the motor 24 detected by the rotation sensor 37 to the rotational speed of the crankshaft 10a shown in Figure 2. In this embodiment, the converted speed is the rotational speed of the output shaft 21 associated with the driving of the motor 24. In step S41, the control unit 31b calculates the converted speed based on the reduction ratio of the reducer 25 of the drive unit 19 and the value detected by the rotation sensor 37. The reduction ratio of the reducer 25 is set in advance. The reduction ratio of the reducer 25 is stored, for example, in the storage unit 31a of the control device 31. The control unit 31b calculates the converted speed by multiplying the value detected by the rotation sensor 37 by the reduction ratio of the reducer 25 stored in the storage unit 31a.

[0195] In step S42 shown in Figure 17, the control unit 31b applies a low-pass filter to the converted speed calculated in step S41. After performing the processing in step S42, the control unit 31b proceeds to step S43.

[0196] In step S43, the control unit 31b proceeds to step S44 if the converted speed and the cadence detected by the cadence sensor 34 are greater than a predetermined threshold. The control unit 31b proceeds to step S51 if at least one of the converted speed and cadence is less than or equal to a predetermined threshold. The predetermined threshold is 5 rpm. The predetermined threshold is not limited to this embodiment as long as it is greater than zero rpm.

[0197] In step S44, the control unit 31b calculates the difference between the converted speed and the cadence detected by the cadence sensor 34. The control unit 31b calculates the difference by subtracting the cadence from the converted speed. By calculating the difference, the control unit 31b detects the difference between the rotational speed of the output shaft 21 due to the drive of the motor 24 and the rotational speed of the crank shaft 10a due to pedaling. After performing the processing in step S44, the control unit 31b proceeds to step S45.

[0198] In step S45, if the control unit 31b determines that the clutch is currently disengaged, it proceeds to step S46. For example, if the determination value in the previous engagement state determination flow was that the clutch was disengaged, the control unit 31b proceeds to step S46. If the control unit 31b does not determine that the clutch is currently disengaged, it proceeds to step S48.

[0199] In step S46, if the difference calculated in step S44 is less than a predetermined threshold, the control unit 31b proceeds to step S47. In step S46, if the difference calculated in step S44 is greater than or equal to a predetermined threshold, the control unit 31b proceeds to step S50. The predetermined threshold is 10 rpm. The predetermined threshold is not limited to this embodiment, as long as it is large enough to distinguish between the clutch disengaged state and the clutch engaged state. When the clutch is disengaged, the converted speed is basically equal to or greater than the cadence, so it is desirable that the predetermined threshold be zero rpm or greater.

[0200] In step S47, the control unit 31b determines that the first one-way clutch 23 is in a clutch-engaged state. After performing the process in step S47, the control unit 31b terminates the engagement state determination flow.

[0201] In step S48, if the difference calculated in step S44 is greater than a predetermined threshold, the control unit 31b proceeds to step S49. If the difference calculated in step S44 is less than or equal to a predetermined threshold, the control unit 31b proceeds to step S50. The predetermined threshold is 15 rpm. The predetermined threshold is not limited to this embodiment, as long as it is large enough to distinguish between the clutch disengaged state and the clutch engaged state. Preferably, the predetermined threshold is zero rpm or greater.

[0202] In step S49, the control unit 31b determines that the first one-way clutch 23 is in a disengaged state. After performing the process in step S49, the control unit 31b terminates the engagement state determination flow.

[0203] In step S50, the control unit 31b retains the previous determination value. As a result of the processing in step S50, the determination value for the current engagement state determination flow becomes the same as the determination value for the previous engagement state determination flow.

[0204] For example, if the clutch is currently disengaged and the difference calculated in step S44 is 10 rpm or more, the control unit 31b proceeds from step S46 to step S50 and determines that the first one-way clutch 23 is disengaged. For example, if the clutch is currently engaged and the difference calculated in step S44 is 15 rpm or less, the control unit 31b proceeds from step S48 to step S50 and determines that the first one-way clutch 23 is engaged. After performing the processing in step S50, the control unit 31b terminates the engagement state determination flow.

[0205] In step S51, which is initiated when at least one of the converted speed and cadence is 5 rpm or less in step S43, the control unit 31b determines that the first one-way clutch 23 is in a clutch-engaged state. After performing the processing in step S51, the control unit 31b terminates the engagement state determination flow.

[0206] By executing the engagement state determination flow, the control unit 31b determines whether the first one-way clutch 23 is in a disengaged state based on the difference between the converted speed and the cadence. Since the converted speed corresponds to the rotational speed of the motor 24, by executing the engagement state determination flow, the control unit 31b can detect the clutch engagement or disengagement state of the one-way clutch based on the rotational speed of the motor 24 and the cadence of the crank arm 10b of the human-powered vehicle 1. For example, a disengaged state can be detected when the rotational speed of the motor 24 is large enough relative to the cadence to rotate the front sprocket 16d by the motor 24.

[0207] Figure 18 is used to illustrate a specific example of the engagement state determination flow. The vertical axis in Figure 18(a) represents torque, cadence, and speed. The horizontal axis in Figures 18(a) and 18(b) represents time. Graph G31 in Figure 18(a) is a graph showing an example of human-powered torque input to pedal 10c. Graph G32 in Figure 18(a) is a graph showing an example of cadence. Graph G33 in Figure 18(a) is a graph showing an example of converted speed to which a low-pass filter has been applied in step S42 shown in Figure 17. Graph G34 in Figure 18(a) is a graph showing an example of converted speed to which a low-pass filter has been applied in step S42. In Figure 18(a), human-powered torque, cadence, and converted speed change over time.

[0208] Figure 18(b) shows the determination values ​​for the engagement state determination flow during the same time period as Figure 18(a). Disengagement shown in Figure 18(b) indicates that the determination value is in the clutch disengaged state. Engagement shown in Figure 18(b) indicates that the determination value is in the clutch engaged state.

[0209] As shown in graph G34, the converted speed before applying the low-pass filter is prone to rapid fluctuations. For example, the converted speed before applying the low-pass filter is more prone to rapid fluctuations than cadence. The control unit 31b can suppress fluctuations in the converted speed by applying a low-pass filter to it. By suppressing fluctuations in the converted speed, the control unit 31b can make it difficult to repeatedly and alternately determine the clutch disengaged state and the clutch engaged state in a short period of time. By making it difficult to repeatedly and alternately determine the clutch disengaged state and the clutch engaged state in a short period of time, the control unit 31b can stabilize the assist torque and improve driving comfort.

[0210] At time T31 shown in Figure 18, pedaling begins and the cadence increases from zero rpm. The cadence at time T31 is zero rpm. Since the cadence at time T31 is 5 rpm or less, the control unit 31b performs the process of step S51 shown in Figure 17 and determines that the first one-way clutch 23 is in a clutch-engaged state.

[0211] In Figure 18, the motor 24 is driven after the cadence has increased. As shown in graph G33 in Figure 18(a), the converted speed increases from zero rpm at time T32, which is later than time T31, as the motor 24 is driven. The converted speed at time T32 shown in Figure 18(a) is zero rpm. Since the converted speed is 5 rpm or less, at time T32, the control unit 31b performs the process of step S51 shown in Figure 17 and determines that the first one-way clutch 23 is in a clutch-engaged state.

[0212] The conversion speed tends to increase rapidly when it starts from zero rpm. The control unit 31b does not apply a low-pass filter when the conversion speed is low. For example, as shown in Figure 17, the low-pass filter is not applied when the conversion speed is 20 rpm or less. By not applying the low-pass filter to the conversion speed when the conversion speed is low, the control unit 31b can suppress the lag between the conversion speed calculated by the control unit 31b and the actual conversion speed when the conversion speed increases from zero rpm.

[0213] The converted speed tends to change rapidly before and after the motor 24 stops. The converted speed before and after the motor 24 stops is relatively small. Since the control unit 31b does not apply a low-pass filter when the converted speed is small, it can suppress the delay between the converted speed calculated by the control unit 31b and the actual converted speed before and after the motor 24 stops.

[0214] In Figure 18(a), the converted speed increases more significantly than the cadence when starting from zero rpm. After applying the low-pass filter, the converted speed is 15 rpm greater than the cadence at time T33. If the converted speed after applying the low-pass filter is 15 rpm greater than the cadence, the control unit 31b performs step S49 shown in Figure 17. By performing the process in step S49, the control unit 31b determines that the first one-way clutch 23 is in a disengaged state at time T33, as shown in Figure 18(b).

[0215] As shown in Figure 18(a), after it is determined that the first one-way clutch 23 is in a clutch-disengaged state, the cadence increases significantly above the converted speed. Between time T33 and time T34, which is after time T33, the cadence increases until the difference between it and the converted speed is less than 10 rpm. When the difference between the cadence and the converted speed is less than 10 rpm, the control unit 31b performs the process of step S47 shown in Figure 17. By performing the process of step S47, the control unit 31b determines that at time T34, the first one-way clutch 23 is in a clutch-engaged state, as shown in Figure 18(b).

[0216] In this embodiment, the control unit 31b determines the engagement state of the one-way clutch using thresholds of different magnitudes depending on the clutch engagement state and the clutch disengagement state, as shown in time T33 and time T34 in Figure 18(a). The engagement threshold used when the clutch is engaged is greater than the disengagement threshold used when the clutch is disengagement. The engagement threshold is the threshold used at time T33. The engagement threshold is the threshold in step S49 shown in Figure 17. The disengagement threshold is the threshold used at time T34. The disengagement threshold is the threshold in step S46.

[0217] By making the engagement threshold greater than the disengagement threshold, the control unit 31b can make it difficult to repeatedly and alternately determine the clutch disengaged state and the clutch engaged state in a short period of time. By making it difficult to repeatedly and alternately determine the clutch disengaged state and the clutch engaged state in a short period of time, the control unit 31b can stabilize the assist torque and improve driving comfort. The relationship between the engagement threshold and the disengagement threshold is not limited to this embodiment. For example, the engagement threshold may be equal to the disengagement threshold.

[0218] In this embodiment, the engagement threshold and the disengagement threshold are greater than zero rpm. By making the engagement threshold and the disengagement threshold greater than zero rpm, for example, if an error occurs between the difference calculated by the control unit 31b in the engagement state determination flow and the actual difference, it becomes difficult to determine that the clutch is disengaged. By making it difficult to determine that the clutch is disengaged when an error occurs, it is possible to suppress an unintended decrease in assist torque.

[0219] Figures 11, 19, and 20 are used to illustrate the predetermined reference assist torque used in step S7 shown in Figure 10. In this embodiment, the control unit 31b switches to the assist-enabled state after the front wheel 15a has rotated in order to appropriately control the motor 24 without using the torque sensor's detected value.

[0220] The acceleration resistance increases when the human-powered vehicle 1 accelerates. In this embodiment, the total torque increases as the acceleration resistance increases, and the assist torque increases as a result. The assist torque in this embodiment increases as a result of the human-powered vehicle 1 accelerating due to human torque. When the assist is switched to the assist-enabled state after the front wheel 15a has rotated, and the assist torque increases as a result of the human-powered vehicle 1 accelerating due to human torque, there is a possibility that the assist torque will be insufficient. For example, there is a possibility that the assist torque will be insufficient when the rider starts to pedal 10c. If the assist torque is insufficient, the pedal 10c is likely to remain heavy, which may impair the comfort of riding.

[0221] The predetermined reference assist torque in this embodiment is an assist torque that allows the human-powered vehicle 1 to accelerate by a predetermined acceleration when the rider starts pedaling the pedal 10c. For example, if the predetermined reference assist torque is applied to the human-powered vehicle 1 when the rider starts pedaling the pedal 10c, a deficiency in assist force can be suppressed. In order to apply the predetermined reference assist torque to the human-powered vehicle 1 when the rider starts pedaling the pedal 10c, the control unit 31b needs to know whether or not the rider is pedaling.

[0222] To determine whether the rider is pedaling or not, the control unit 31b is configured to determine the pedal state of the pedal 10c. As shown in Figure 11, the control unit 31b is configured to detect the pedal state separately from the process of step S6 which calculates the assist torque. The pedal state is information indicating the state in which the rider is pedaling. As shown in Figure 20, the pedal state includes the stop state, zero start state, pedaling state, coasting state, and restart state.

[0223] The stop state is when the human-powered vehicle 1 is stopped and the rider has not started pedaling. The zero-start state is when the rider starts pedaling from a stopped state. The control unit 31b detects that the vehicle has transitioned from the stop state to the zero-start state when the vehicle speed detected by the vehicle speed sensor 33 is greater than zero km / h and the cadence detected by the cadence sensor 34 is greater than zero rpm.

[0224] The pedaling state is the state in which the human-powered vehicle 1 is moving and the rider is pedaling. The control unit 31b detects that the system has transitioned from the zero-start state to the pedaling state when the crank 10 has rotated by a predetermined target amount of crank rotation after transitioning to the zero-start state. In this embodiment, the target amount of crank rotation is 720 degrees. The target amount of crank rotation is not limited to this embodiment.

[0225] The coasting state is a state in which the human-powered vehicle 1 is moving and the rider is not pedaling. The control unit 31b detects that the system has transitioned from the zero-start state or the pedaling state to the coasting state when the cadence detected by the cadence sensor 34 becomes zero rpm in either the zero-start state or the pedaling state.

[0226] The restart state is the state in which the rider starts pedaling from the coasting state. The control unit 31b detects that the system has transitioned to the restart state when the cadence detected by the cadence sensor 34 is greater than a predetermined threshold while in the coasting state. The predetermined threshold is 30 rpm. The predetermined threshold is not limited to this embodiment, as long as it is large enough to detect the restart state. The control unit 31b detects that the system has transitioned to the coasting state when the cadence becomes zero rpm while in the restart state.

[0227] The control unit 31b detects that the system has transitioned from the restart state to the pedaling state when the crank 10 has rotated by a predetermined target amount after transitioning to the restart state. In this embodiment, the target amount of crank rotation is 720 degrees. The target amount of crank rotation is not limited to this embodiment.

[0228] The control unit 31b detects that the vehicle speed detected by the vehicle speed sensor 33 becomes zero km / h in any one of the pedaling state, coasting state, or restart state, and that the vehicle has transitioned from one of these states to the stop state.

[0229] The control unit 31b can determine whether the rider is pedaling the pedals 10c by detecting the pedal state. For example, the control unit 31b can determine that the rider is pedaling the pedals 10c if the pedal state is either the zero-start state or the restart state. The control unit 31b stores the current pedal state in the storage unit 31a.

[0230] Figures 11 and 19 are used to illustrate the torque update flow for updating a predetermined reference assist torque. As shown in Figure 11, the control unit 31b executes the torque update flow separately from the process in step S6 for calculating the assist torque. For example, the control unit 31b repeats the torque update flow at predetermined time intervals. By the control unit 31b repeating the torque update flow, the predetermined reference assist torque is updated when pedaling stops. Once the control unit 31b starts the torque update flow, it proceeds to step S61 shown in Figure 19.

[0231] In step S61, the control unit 31b calculates the acceleration in the direction of travel of the human-powered vehicle 1 by differentiating the vehicle speed detected by the vehicle speed sensor 33, for example. The control unit 31b applies a low-pass filter to the calculated acceleration. After performing the processing in step S61, the control unit 31b proceeds to step S62.

[0232] In step S62, the control unit 31b obtains the current pedal state. For example, the control unit 31b obtains the current pedal state from the storage unit 31a. After performing the processing in step S62, the control unit 31b proceeds to step S63.

[0233] In step S63, the control unit 31b moves to a different step depending on the current pedal state acquired in step S63. If the current pedal state is the stop state, the control unit 31b moves to step S64. If the current pedal state is the coasting state, the control unit 31b moves to step S69. If the current pedal state is the pedaling state, the zero start state, or the restart state, the control unit 31b terminates the torque update flow.

[0234] In step S64, the control unit 31b calculates the slope at the location where the human-powered vehicle 1 stops. In the description of the torque update flow, the slope until the final determination is made is described as the provisional slope value while stationary. The control unit 31b calculates the provisional slope value while stationary based, for example, on the acceleration of the human-powered vehicle 1 detected by the acceleration sensor 36. The unit of the provisional slope value while stationary is %. After performing the processing in step S64, the control unit 31b proceeds to step S65.

[0235] In step S65, if the difference between the maximum and minimum values ​​of the provisional slope while stationary, calculated within a predetermined period, is less than a predetermined threshold, the control unit 31b proceeds to step S66. If the difference between the maximum and minimum values ​​of the provisional slope while stationary is greater than or equal to a predetermined threshold, the control unit 31b proceeds to step S67. In this embodiment, the predetermined period is the period from the present to 0.5 ms ago. The predetermined threshold is 1%. The predetermined period and the predetermined threshold are not limited to this embodiment.

[0236] In step S66, the control unit 31b determines the slope at the location where the human-powered vehicle 1 stops. The control unit 31b determines the provisional value of the slope while stopped, calculated in step S64, as the slope at the location where the human-powered vehicle 1 stops. After performing the processing in step S66, the control unit 31b proceeds to step S68.

[0237] In step S67, the control unit 31b holds the previously calculated inclination value. Through the processing of step S67, the control unit 31b determines the inclination calculated in the previous torque update flow as the current inclination. After performing the processing of step S67, the control unit 31b proceeds to step S68.

[0238] In step S68, the control unit 31b updates the predetermined reference assist torque based on the inclination determined in step S66 or step S67. The procedure for updating the predetermined reference assist torque in step S68 will be described later. After performing the processing of step S68, the control unit 31b ends the torque update flow.

[0239] In step S69, which is executed when the current pedal state is the coasting state in step S63, the control unit 31b updates the predetermined reference assist torque. The procedure for updating the predetermined reference assist torque in step S69 will be described later. After performing the processing of step S69, the control unit 31b ends the torque update flow.

[0240] The procedure for updating the predetermined reference assist torque in step S68 will be described. When cadence is denoted as C, tire circumference as TC, and gear ratio as GR, the vehicle speed S of the human-powered vehicle 1 is expressed by the following Equation 14. (Equation 14) S[m / s] = (C[rpm] / 60) × TC[m] × GR[-]

[0241] Substituting the vehicle speed S of Equation 14 into the vehicle speed S in Equation 13 for calculating the provisional total torque value, the running resistance F in Equation 13 t incorporates the acceleration resistance F in Equation 1 a and the gradient resistance F in Equation 2 g , the total torque T t is expressed by the following Equation 15. (Equation 15) T t = (M[kg] × a[m / s 2 + M[kg] × g[m / s 2 × sinθ[rad]) × TC[m] × GR[-] × (1 / 2π)

[0242] Total torque T in Equation 15 t This is the torque when the human-powered vehicle 1 accelerates with acceleration a. The predetermined reference assist torque is the assist torque that allows the human-powered vehicle 1 to accelerate with a predetermined acceleration when the rider starts pedaling pedal 10c. The predetermined reference assist torque T tg This is expressed by the following equation 16, which replaces the acceleration a in equation 15 with a predetermined acceleration K. (Formula 16)T tg =(M[kg]×K[m / s 2 ]+M[kg]×g[m / s 2 ]×sinθ[rad])×TC[m]×GR[-]×(1 / 2π)

[0243] In step S68, the control unit 31b calculates a predetermined reference assist torque using equation 16. In step S66 or step S67, the control unit 31b converts the incline determined in step S66 or step S67 into sinθ and substitutes it into sinθ in equation 16. For example, the control unit 31b substitutes the weight M, acceleration K, gravitational acceleration g, and tire circumference TC of the human-powered vehicle 1 stored in the memory unit 31a into the weight M, acceleration K, gravitational acceleration g, and tire circumference TC in equation 16.

[0244] If the human-powered vehicle 1 is equipped with a gear position sensor to detect the gear ratio, the control unit 31b substitutes the value detected by the gear position sensor into the gear ratio GR in Equation 16. If the human-powered vehicle 1 is not equipped with a gear position sensor, the control unit 31b estimates the gear ratio and substitutes it into the gear ratio GR in Equation 16. Figure 21 shows the gear ratio estimation flow for estimating the gear ratio. The gear ratio estimation flow will be described later.

[0245] The control unit 31b updates the predetermined reference assist torque by storing the predetermined reference assist torque calculated using Equation 16 in the storage unit 31a. By calculating the predetermined reference assist torque using Equation 16, the control unit 31b can determine the assist force for starting to pedal based on a predetermined acceleration at the start of pedaling, the slope of the road surface where the human-powered vehicle 1 stops, and the vehicle information of the human-powered vehicle 1. The acceleration at the start of pedaling corresponds to the acceleration K in Equation 16. The slope of the road surface corresponds to the slope sinθ in Equation 16. The assist force for starting to pedal corresponds to the assist torque determined in step S7 of Figure 10 using the predetermined reference torque.

[0246] Vehicle information includes at least one of the total weight, tire circumference, and gear ratio of the human-powered vehicle 1. In this embodiment, vehicle information includes the total weight, tire circumference, and gear ratio of the human-powered vehicle 1. The total weight corresponds to the weight M in Equation 16. The tire circumference corresponds to the tire circumference TC in Equation 16. The gear ratio corresponds to the gear ratio GR in Equation 16.

[0247] The control unit 31b can appropriately control the assist force by determining the assist force at the start of pedaling based on the acceleration at the start of pedaling, the slope of the road surface on which the human-powered vehicle 1 is stopped, and the vehicle information of the human-powered vehicle 1. For example, when the rider starts pedaling the pedal 10c, the control unit 31b can apply an assist torque to the human-powered vehicle 1 that allows it to accelerate by a predetermined acceleration.

[0248] If the temporary incline value changes significantly while the vehicle is stopped, the control unit 31b calculates a predetermined reference assist torque in step S68 using the previous incline. By calculating the predetermined reference assist torque using the previous incline, the predetermined reference assist torque becomes stable.

[0249] For example, the temporary incline value while stationary is likely to change significantly immediately after the human-powered vehicle 1 stops and at the moment the human-powered vehicle 1 starts moving. When the temporary incline value while stationary changes significantly, errors are likely to occur. When the temporary incline value while stationary changes significantly, the control unit 31b calculates a predetermined reference assist torque using the previous incline. By calculating the predetermined reference assist torque using the previous incline, the influence of errors in the temporary incline value while stationary is suppressed, and the predetermined reference assist torque becomes stable.

[0250] The procedure for updating the predetermined reference assist torque in step S69 is described. The control unit 31b calculates the predetermined reference assist torque T in the coasting state by the following equation 17 obtained by removing the gradient resistance from equation 16. tg The control unit 31b calculates the predetermined reference assist torque. The control unit 31b updates the predetermined reference assist torque by storing the calculated predetermined reference assist torque in the storage unit 31a. (Formula 17)T tg =M[kg]×K[m / s 2 ]×TC[m]×GR[-]×(1 / 2π)

[0251] In step S69, the control unit 31b updates the predetermined reference assist torque when the vehicle is coasting. The slope in the coasting state is more prone to change than the slope in the stopped state. When the slope is prone to change, the slope calculated by the control unit 31b is prone to errors compared to the actual slope. Because errors are likely to occur in the coasting state compared to the actual slope, the control unit 31b calculates the predetermined reference assist torque without considering the slope shown in equation 16. In equation 16, the slope is used to calculate the gradient resistance, so the control unit 31b calculates the predetermined reference assist torque using equation 17, which is obtained by removing the gradient resistance from equation 16.

[0252] By calculating a predetermined reference assist torque using Equation 17, the control unit 31b can calculate the predetermined reference assist torque without being affected by the slope error, thus stabilizing the predetermined reference assist torque.

[0253] The acceleration K in Equation 16 and the acceleration K in Equation 17 may be different values. For example, the acceleration K in Equation 16 may be greater than the acceleration K in Equation 17. For example, if the acceleration K in Equation 16 is 0.25 G m / s² 2 This is the converted value, and the acceleration K in Equation 17 is 0.1G in m / s². 2 The value may be the converted value.

[0254] Because the acceleration K in Equation 16 is greater than the acceleration K in Equation 17, the control unit 31b can apply a relatively large assist torque to the human-powered vehicle 1 when the rider starts pedaling 10c from a stop. For example, the control unit 31b can apply a larger assist torque to the human-powered vehicle 1 than when the rider starts pedaling 10c from a coasting state. By applying a relatively large assist torque to the human-powered vehicle 1, the control unit 31b can reduce the burden on the rider and improve riding comfort when the rider starts pedaling 10c from a stop state where the pedal 10c is relatively heavy.

[0255] Figures 11 and 21 are used to illustrate the gear ratio estimation flow for estimating the gear ratio. As shown in Figure 11, the control unit 31b executes the gear ratio estimation flow separately from the torque update flow. For example, the control unit 31b repeats the gear ratio estimation flow at predetermined intervals. In the gear ratio estimation flow, the control unit 31b calculates the gear ratio inversely from the rotational speed and cadence of the wheel 15. In the explanation of the gear ratio estimation flow, the gear ratio during the estimation process is described as a provisional estimated gear ratio. When the control unit 31b starts the gear ratio estimation flow, it proceeds to step S71 shown in Figure 21.

[0256] In step S71, the control unit 31b acquires the detected cadence value from the cadence sensor 34 and applies a low-pass filter to the acquired detected value. After performing the processing in step S71, the control unit 31b proceeds to step S72.

[0257] In step S72, the control unit 31b acquires the tire circumference stored in the storage unit 31a. After performing the process of step S72, the control unit 31b proceeds to step S73.

[0258] In step S73, if the tire circumference acquired in step S72 is not zero m, the control unit 31b proceeds to step S74. If the tire circumference acquired in step S72 is zero m, the control unit 31b proceeds to step S79. When the tire circumference acquired in step S72 is a negative value, the control unit 31b may proceed to step S79.

[0259] In step S74, the control unit 31b determines whether there is a possibility that the error between the gear ratio estimated in the gear ratio estimation flow and the actual gear ratio is large. When determining that there is no possibility of a large error, the control unit 31b proceeds to step S75. When determining that there is a possibility of a large error, the control unit 31b proceeds to step S79. The determination condition in step S74 will be described later.

[0260] In step S75, the control unit 31b calculates the rotation speed of the wheel 15 of the human-powered vehicle 1 when the wheel 15 makes one full rotation. For example, the control unit 31b divides the latest average value of the vehicle speed detected by the vehicle speed sensor 33 during one full rotation of the wheel 15 by the tire circumference acquired in step S72, and converts the result to rpm, thereby calculating the rotation speed of the wheel 15. After performing the process of step S75, the control unit 31b proceeds to step S76.

[0261] In step S76, the control unit 31b calculates a provisional estimated gear ratio using the cadence to which the low-pass filter has been applied in step S71 and the rotation speed of the wheel 15 calculated in step S75. The control unit 31b calculates the provisional estimated gear ratio, for example, by dividing the rotation speed of the wheel 15 by the cadence. Through the process of step S76, the control unit 31b back-calculates the gear ratio from the cadence and the rotation speed of the wheel 15.

[0262] The rotational speed of wheel 15 is calculated in step S75 from the vehicle speed of the human-powered vehicle 1. Since the rotational speed of wheel 15 is calculated from the vehicle speed, in step S76 the control unit 31b can determine the gear ratio based on the vehicle speed and cadence of the human-powered vehicle 1. After performing the processing in step S76, the control unit 31b proceeds to step S77.

[0263] In step S77, the control unit 31b proceeds to step S77 if the estimated provisional gear ratio is stable. If the estimated provisional gear ratio is not stable, the control unit 31b proceeds to step S78. For example, the control unit 31b may determine that the estimated provisional gear ratio is stable if the difference between the maximum and minimum values ​​of the estimated provisional gear ratio calculated within a predetermined period is less than a predetermined threshold. In this embodiment, the predetermined period is the period from the present to 0.5 ms ago. The predetermined threshold is 0.15. The predetermined period and the predetermined threshold are not limited to this embodiment.

[0264] In step S78, the control unit 31b determines the gear ratio of the human-powered vehicle 1. The control unit 31b uses the estimated provisional gear ratio calculated in step S76 as the gear ratio of the human-powered vehicle 1. After performing the processing in step S78, the control unit 31b terminates the gear ratio estimation flow.

[0265] In step S79, the control unit 31b retains the previous gear ratio estimate. As a result of the processing in step S79, the current gear ratio estimate in the gear ratio estimation flow becomes the same as the previous gear ratio estimate in the gear ratio estimation flow. After performing the processing in step S79, the control unit 31b terminates the gear ratio estimation flow.

[0266] The control unit 31b can acquire the gear ratio in a human-powered vehicle 1 that does not have a gear sensor by executing a gear ratio estimation flow. Because the control unit 31b can acquire the gear ratio in a human-powered vehicle 1 that does not have a gear sensor, the control device 31 can be applied to the human-powered vehicle 1 that does not have a gear sensor, thus improving its versatility.

[0267] In step S71, the control unit 31b applies a low-pass filter to the cadence. Since the cadence after applying the low-pass filter fluctuates less than the cadence before applying the low-pass filter, the control unit 31b can estimate the gear ratio using a variable with less fluctuation by applying the low-pass filter to the cadence. By estimating the gear ratio using a variable with less fluctuation, the estimated gear ratio becomes stable.

[0268] The control unit 31b retains the previous estimated gear ratio if the determination process in step S74 indicates that there is a possibility of a large error in the estimated gear ratio. In this embodiment, the control unit 31b determines that there is a possibility of a large error when at least one of the following conditions is met: the cadence is 30 rpm or less, the vehicle speed is 10 km / h or less, and the first one-way clutch 23 is in the clutch engaged state, and retains the previous estimated gear ratio.

[0269] The relationship between the estimated gear ratio and cadence is explained. In step S76, the control unit 31b calculates a provisional estimated gear ratio by dividing the rotational speed of the wheel 15 by the cadence. When the rotational speed of the wheel 15 is divided by the cadence, the provisional estimated gear ratio jumps up as the cadence approaches zero rpm. When the provisional estimated gear ratio jumps up, it tends to become larger than the actual gear ratio. Because when the provisional estimated gear ratio jumps up, it tends to become larger than the actual gear ratio, the control unit 31b, in the processing of step S74, proceeds to step S79 and retains the previous estimated gear ratio when the cadence is relatively small.

[0270] By retaining the previous gear ratio estimate, the control unit 31b can reduce errors in the gear ratio estimate caused by cadence. By retaining the previous gear ratio estimate, the control unit 31b can estimate the gear ratio when the cadence is zero rpm. The threshold value compared with the cadence in step S74 is not limited to this embodiment as long as it is greater than zero rpm.

[0271] The relationship between the estimated gear ratio and vehicle speed is explained. The rotational speed of the wheel 15 calculated in step S75 is calculated based on the vehicle speed detected by the vehicle speed sensor 33. In this embodiment, the vehicle speed sensor 33 detects the vehicle speed in response to multiple pulse signals output from the wheel speed sensor 33a while the front wheel 15a rotates once.

[0272] If multiple pulse signals are output during one rotation of the front wheel 15a, the vehicle speed detected by the vehicle speed sensor 33 is prone to errors when the human-powered vehicle 1 is traveling at a relatively slow speed. For example, the vehicle speed sensor 33 may temporarily detect a vehicle speed higher than the actual speed. If there is an error in the vehicle speed detected by the vehicle speed sensor 33, an error will occur in the rotational speed of the wheel 15 calculated in step S75, resulting in an error between the actual gear ratio and the estimated gear ratio.

[0273] If the vehicle speed is relatively low, the control unit 31b proceeds to step S79 to retain the previous estimated gear ratio value after processing in step S74. By retaining the previous estimated gear ratio value, the control unit 31b can reduce the error in the estimated gear ratio value caused by the vehicle speed.

[0274] The relationship between the estimated gear ratio and the clutch engagement state of the first one-way clutch 23 is explained. In step S76, the control unit 31b calculates the gear ratio from the rotational speed and cadence of the wheel 15. The gear ratio can be calculated from the rotational speed and cadence of the wheel 15 only when the first one-way clutch 23 is in the clutch engagement state.

[0275] Since the gear ratio can only be calculated from the rotational speed and cadence of the wheel 15 when the first one-way clutch 23 is engaged, the control unit 31b proceeds to step S79 in step S74 if the first one-way clutch 23 is not engaged, and retains the previous estimated gear ratio. By retaining the previous estimated gear ratio when the clutch is not engaged, the control unit 31b can reduce the error in the estimated gear ratio.

[0276] The process of step S7 shown in Figure 10 is explained. In the explanation of the process of step S7, the assist torque calculated in step S6 is described as the assist torque before determination. The assist torque determined in the process of step S7 is described as the assist torque after determination. In step S7, the control unit 31b determines the assist torque using the predetermined reference assist torque updated by the torque update flow shown in Figure 19 and the assist torque before determination. The control unit 31b determines the assist torque so that it does not fall outside the range between the predetermined reference assist torque and the assist torque before determination.

[0277] In this embodiment, the control unit 31b controls a predetermined reference assist torque T tg The assist torque before the decision is set to T a Using the following equation 17, with weighting coefficient W, the determined assist torque T' is calculated. a Calculate. (Formula 17)T´ a =T tg ×W+T a ×(1-W)

[0278] The weighting coefficient is a variable used to define the ratio between the assist torque before determination and a predetermined reference assist torque. The weighting coefficient is defined, for example, within a range between zero and one. Since the predetermined reference assist torque is greater than the assist torque before determination, the closer the weighting coefficient is to one, the larger the assist torque after determination.

[0279] The control unit 31b calculates weighting coefficients according to predetermined parameters. The predetermined parameters may include, for example, the amount of rotation of the crank 10 after the rider starts pedaling the pedal 10c. In this embodiment, the predetermined parameters include the amount of rotation of the crank 10 after the rider starts pedaling the pedal 10c, the zero start state, and the restart state.

[0280] Figure 22 shows an example of the relationship between the weighting coefficient in the zero-start state and the amount of rotation of the crank arm 10b. The amount of rotation of the crank arm 10b shown in Figure 22 is the amount of rotation of the crank arm 10b after the pedal state transitions to the zero-start state.

[0281] The control unit 31b increases the weighting coefficient from zero to 1 when the amount of rotation of the crank 10 goes from zero to a predetermined first rotation amount X1. The control unit 31b sets the weighting coefficient to 1 when the amount of rotation of the crank 10 goes from the first rotation amount X1 to a predetermined third rotation amount X3. The control unit 31b decreases the weighting coefficient from 1 to zero when the amount of rotation of the crank 10 goes from the third rotation amount X3 to a fourth rotation amount X4.

[0282] Figure 23 shows an example of the relationship between the weighting coefficient in the restart state and the amount of rotation of the crank arm 10b of the crank 10. The control unit 31b sets the weighting coefficient to zero while the amount of rotation of the crank arm 10b is from zero to the first rotation amount X1. The control unit 31b increases the weighting coefficient from zero to 1 while the amount of rotation of the crank arm 10b is from the first rotation amount X1 to the second rotation amount X2, which is greater than the first rotation amount X1. By increasing the weighting coefficient from zero to 1 while the amount of rotation of the crank arm 10b is from the first rotation amount X1 to the second rotation amount X2, the control unit 31b increases the assist torque at speeds slower than the restart state.

[0283] When the human-powered vehicle 1 is coasting, if a relatively small human-powered torque is input to the human-powered vehicle 1, the control unit 31b may apply assist torque to the human-powered vehicle 1. If assist torque is applied to the human-powered vehicle 1 when a relatively small human-powered torque is input to the crank 10, the one-way clutch and other components provided in the power transmission path from the rear sprocket 16e to the rear wheel 15b may engage forcefully, potentially generating noise and shock.

[0284] The control unit 31b increases the assist torque at speeds slower than the restart state, thereby suppressing the forceful engagement of the one-way clutch and other components in the power transmission path from the rear sprocket 16e to the rear wheel 15b, and making it less likely to generate noise and shock.

[0285] The control unit 31b sets the weighting coefficient to 1 while the amount of rotation of the crank arm 10b changes from the second rotation amount X2 to the third rotation amount X3. The control unit 31b then reduces the weighting coefficient from 1 to zero while the amount of rotation of the crank arm 10b changes from the third rotation amount X3 to the fourth rotation amount X4.

[0286] In step S7 shown in Figure 10, the control unit 31b determines the assist torque by substituting a weighting coefficient determined according to the amount of rotation of the crank arm 10b into the weighting coefficient W of Equation 17. By determining the assist torque using the weighting coefficient W, the control unit 31b can determine the assist force as the assist force for starting to pedal, based on a predetermined reference assist force, when the amount of rotation of the crank arm 10b of the human-powered vehicle 1 is less than or equal to a predetermined amount of rotation.

[0287] For example, the control unit 31b can determine the assist force based on a predetermined reference assist force when the amount of rotation of the crank arm 10b after transitioning to the zero-start state is less than or equal to the fourth rotation amount X4 shown in Figure 22. For example, the control unit 31b can determine the assist force based on a predetermined reference assist force when the amount of rotation of the crank arm 10b after transitioning to the restart state is within the range from the first rotation amount X1 to the fourth rotation amount X4 shown in Figure 23.

[0288] By determining the assist force based on a predetermined reference assist force, the control unit 31b can apply a relatively large assist force to the human-powered vehicle 1 when the rider starts pedaling the pedals 10c. This allows the human-powered vehicle 1 to accelerate more easily when the rider starts pedaling the pedals 10c, thereby improving riding comfort.

[0289] When the first one-way clutch 23 is in a disengaged state, the human-powered torque is considered to be relatively small. When determining the assist torque using a weighting coefficient, the assist torque may increase compared to before the determination. Therefore, the control unit 31b determines the assist torque without using a weighting coefficient when the first one-way clutch 23 is in a disengaged state, and when the clutch is engaged midway through the start of paddling.

[0290] For example, the control unit 31b determines the assist torque calculated in step S6 as the assist torque to be applied to the human-powered vehicle 1. When the first one-way clutch 23 is in a clutch-disengaged state, by determining the assist torque without using a weighting coefficient, a relatively small assist torque can be applied to the human-powered vehicle 1 when the human-power torque is relatively small.

[0291] (modified version) The description relating to this embodiment is illustrative of possible forms of the present invention and is not intended to limit it. The present invention may take the form of, for example, the following modifications of this embodiment, and at least two non-contradictory modifications combined.

[0292] For example, the configuration of the drive unit 19 in this embodiment is just one example, and the drive unit 19 may include various devices not shown in this embodiment, or it may have a configuration that does not include some of the various devices shown in this embodiment.

[0293] For example, the control unit 31b may be configured to switch from the assist-disabled state shown in Figure 4 to the assist-disabled state depending on either the vehicle speed information or the distance traveled information. For example, the control unit 31b may determine the assist force using the driving resistance calculated according to at least one of the acceleration resistance, gradient resistance, and rolling resistance.

[0294] For example, the control unit 31b may calculate the rolling resistance in the motor control flow shown in Figure 10 when predetermined conditions are met. The predetermined conditions may be the same as the conditions for calculating acceleration resistance and gradient resistance. For example, the control unit 31b may perform a rolling resistance determination process in at least one of the following cases: when the cadence of the crank arm 10b of the human-powered vehicle 1 is greater than a predetermined threshold, and when a predetermined time has elapsed since the rotation of the crank arm 10b of the human-powered vehicle 1 was detected. The rolling resistance determination process corresponds to the process in step S4.

[0295] For example, if the human-powered vehicle 1 is equipped with a sensor for detecting the gear ratio, the control unit 31b may omit the gear ratio estimation flow shown in Figure 21. For example, the control unit 31b may calculate the weighting coefficient without considering the zero-start state and the restart state.

[0296] The various thresholds used in the control exemplified in this embodiment are not limited and may be set arbitrarily. The various thresholds may also be arbitrarily changed by operating a predetermined control device or the like.

[0297] The processing content and processing order of the flowchart exemplified in this embodiment are examples only, and the processing content and processing order can be changed as appropriate within the scope of the present invention.

[0298] For example, in the motor control flow shown in Figure 10, the order of the process in step S2 for calculating acceleration resistance, the process in step S3 for calculating gradient resistance, and the process in step S4 for calculating rolling resistance may be changed.

[0299] As used herein, the expression "at least one" means "one or more" of the desired options. For example, as used herein, the expression "at least one" means "only one option" or "both of the two options" if there are two options. As another example, as used herein, the expression "at least one" means "only one option" or "a combination of two or more any options" if there are three or more options. For example, the expression "at least one of A and B" means (1) A only, and (2) B only, and (3) both A and B. For example, the expression "at least one of A, B, and C" means (1) A only, and (2) B only, (3) C only, (4) both A and B, (5) both B and C, (6) both A and C, and (7) all of A, B, and C. In other words, the expression “at least one of A and B” as used herein does not mean “at least one A and at least one B.” [Explanation of Symbols]

[0300] 1...Human-powered vehicle, 10b...Crank arm, 23...First one-way clutch, 24...Motor, 31...Control device, 31b...Control unit

Claims

1. A control device for a human-powered vehicle, The vehicle includes a control unit configured to control a motor that provides assisting force to the human-powered vehicle, The control unit is a control device that determines the assist force according to the driving information and driving resistance information of the human-powered vehicle, without using the detected value of a torque sensor that detects the human-powered torque input to the human-powered vehicle.

2. The control device according to claim 1, wherein the control unit applies the determined assist force to the human-powered vehicle.

3. The control device according to claim 1, wherein the control unit is configured to control the motor in the human-powered vehicle that does not have the torque sensor.

4. The control device according to claim 1, wherein the driving information includes at least one of the vehicle speed, wheel speed, and cadence of the human-powered vehicle.

5. The control device according to claim 1, wherein the running resistance information includes at least one of the acceleration resistance, gradient resistance, and rolling resistance of the human-powered vehicle.

6. The control device according to claim 5, wherein the control unit performs an acceleration resistance determination process to determine the acceleration resistance based on the weight of the human-powered vehicle and the acceleration in the direction of travel.

7. The control device according to claim 6, wherein the control unit performs the acceleration resistance determination process in at least one of the following cases: when the cadence of the crank arm of the human-powered vehicle is greater than a predetermined threshold, and when a predetermined time has elapsed since the rotation of the crank arm of the human-powered vehicle was detected.

8. The control device according to claim 6, wherein the control unit performs a gradient resistance determination process to determine the gradient resistance based on the weight of the human-powered vehicle and the inclination of the road surface on which the human-powered vehicle travels.

9. The control device according to claim 8, wherein the control unit performs the gradient resistance determination process in at least one of the following cases: when the cadence of the crank arm of the human-powered vehicle is greater than a predetermined threshold, and when a predetermined time has elapsed since the rotation of the crank arm of the human-powered vehicle was detected.

10. The control device according to claim 5, wherein the control unit performs a rolling resistance determination process to determine the rolling resistance based on the weight of the human-powered vehicle and the coefficient of friction of the road surface on which the human-powered vehicle travels.

11. The control device according to claim 10, wherein the control unit performs the rolling resistance determination process in at least one of the following cases: when the cadence of the crank arm of the human-powered vehicle is greater than a predetermined threshold, and when a predetermined time has elapsed since the rotation of the crank arm of the human-powered vehicle was detected.

12. The control device according to claim 1, wherein the control unit determines the assist force for starting to pedal based on a predetermined acceleration for starting to pedal, the slope of the road surface on which the human-powered vehicle stops, and vehicle information of the human-powered vehicle.

13. The control device according to claim 1, wherein the control unit determines the assist force as the assist force for starting to pedal, based on a predetermined reference assist force, when the amount of rotation of the crank arm of the human-powered vehicle is less than or equal to a predetermined amount of rotation.

14. The control device according to claim 12), wherein the vehicle information includes at least one of the total weight of the human-powered vehicle, the circumference of the tires, and the gear ratio.

15. The control device according to claim 14, wherein the control unit determines the gear ratio based on the vehicle speed and cadence of the human-powered vehicle.

16. The control device according to claim 1, wherein the control unit reduces the assist force when the cadence drops sharply.

17. The aforementioned human-powered vehicle is provided with a one-way clutch in the power transmission path from the crankshaft to the front sprocket, having a clutch engagement state in which power is transmitted from the crankshaft to the front sprocket when the crankshaft rotates in a first rotational direction, and a clutch disengagement state in which power is not transmitted from the crankshaft to the front sprocket when the crankshaft rotates in a second rotational direction opposite to the first rotational direction. The control device according to claim 1, wherein the control unit reduces the assist force when the one-way clutch is in a disengaged state.

18. The control device according to claim 17, wherein the control unit detects the clutch engagement state or the clutch disengagement state of the one-way clutch based on the rotational speed of the motor and the cadence of the crank arm of the human-powered vehicle.

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